Why Your 2020 RAM 1500 Runs Sick or Misfires (Intake Leak Guide)

How to Fix Exhaust Manifold Issue

For 2020 RAM 1500 owners, addressing concerns related to the exhaust system often involves understanding the connection between intake modifications and performance. While direct reports of cracked or leaking exhaust manifolds are not prevalent in our specific owner data, a common theme emerges: modifications to the intake and exhaust systems can lead to unintended issues, with intake leaks being a primary culprit identified by owners for causing drivability problems. As one owner shared while discussing their upgrade path, "The exhaust would definitely be worth while though and get you more HP, and a nice sound." — TheDarkChunk7 (source). This guide will help you diagnose and resolve the intake-related problems that often manifest with symptoms mistaken for or related to exhaust manifold issues.

Symptoms

Owners report a range of symptoms that can point to an underlying intake leak or irregular airflow, which often gets confused with exhaust problems. The most common descriptor is the truck running "sick," which is a broad term for poor performance, rough idle, or a lack of power. You might notice the engine doesn't feel as responsive as it should, especially during acceleration.

Another key symptom is a misfire. An intake leak introduces unmetered air into the engine, disrupting the carefully calibrated air-fuel ratio. This lean condition can cause one or more cylinders to misfire, leading to a rough running engine, hesitation, and potentially a flashing check engine light. The misfire may be intermittent or constant, depending on the severity of the leak.

Oil leakage in the vicinity of the intake system can also be a sign. While not the leak itself, oil residue around intake gaskets, the throttle body, or the PCV system connections can indicate a failing seal that is also allowing air to seep in. This contamination can sometimes be traced back to other modified components. Furthermore, owners pursuing performance sounds often report on their modifications, with one stating, "Just wrapped up the first round of mods on the truck & I'm loving the results! ...S&B CAI & Borla ATAK exhaust." — Marine4Lyf (source). It's crucial to note that after installing such components, any new drivability issue is likely related to the installation.

Most Likely Cause

Based on the data from 2020 RAM 1500 owners, the most likely cause of the symptoms described is an intake leak. This is specifically highlighted in the owner discussions as a root problem. An intake leak occurs when unmetered air enters the engine after the mass airflow (MAF) sensor. The engine computer (PCM) is delivering fuel based on the air it thinks is coming in through the sensor. Extra air dilutes the mixture, creating a lean condition.

This leak can originate from several places, especially after modifications. A poorly installed or faulty aftermarket cold air intake (CAI) system is a prime suspect. If the clamps are not tight, the intake tube is cracked, or the filter housing doesn't seal properly against the intake box, air will be sucked in. Similarly, a damaged or improperly seated intake manifold gasket can create a vacuum leak. Even a disconnected or cracked vacuum hose attached to the intake manifold can be the source. As one owner critically noted about certain mods, "Stock air box is better than whatever 'CAI' you get. And even if you got a nice one, unless you're doing other upgrades for HP, its just a paper weight." — TheDarkChunk7 (source), hinting at the potential for installation issues with non-OEM parts.

How to Diagnose

Diagnosing an intake leak requires a systematic approach, focusing on listening, looking, and testing. You'll need a few basic tools: a mechanic's stethoscope or a length of heater hose, a can of carburetor cleaner or propane (used with extreme caution), and an OBD2 scanner to read trouble codes.

First, use your OBD2 scanner to check for diagnostic trouble codes (DTCs). Codes like P0171 (System Too Lean Bank 1) or P0174 (System Too Lean Bank 2) are classic indicators of an intake leak. You may also find random misfire codes (P0300-P0308). Next, with the engine cold for safety, start it and let it idle. Listen carefully for a distinct hissing or whistling sound around the intake manifold, throttle body, and all intake tubing. A mechanic's stethoscope can help isolate the sound.

The carburetor cleaner test is a proven method. With the engine idling, carefully spray small bursts of carb cleaner around suspected leak points: intake manifold gasket seams, around the throttle body gasket, all vacuum hose connections, and every joint in the aftermarket CAI system. Warning: Keep the spray away from hot exhaust components. If the engine's idle speed suddenly increases or smooths out when you spray a specific area, you've found your leak. The flammable fluid is being drawn in through the leak, temporarily enriching the mixture and changing the engine speed. Always perform this test in a well-ventilated area with a fire extinguisher nearby.

Step-by-Step Fix

Fixing an intake leak involves inspecting, resealing, or replacing the faulty component. Here is a step-by-step guide based on the most common scenario: a leak at an aftermarket cold air intake connection.

1. Safety First: Disconnect the negative battery cable. Ensure the engine is completely cool before starting.
2. Visual Inspection: Thoroughly examine the entire aftermarket intake system. Look for obvious cracks in the intake tube, loose or missing clamps, and check that the filter is properly seated. Look for any oil residue or dirt streaks that might indicate an air path.
3. Remove the Intake Assembly: Loosen the hose clamps securing the intake tube to the throttle body and the air filter housing. Carefully remove the entire intake tube and filter assembly from the engine bay.
4. Inspect Sealing Surfaces: Check the rubber couplers or silicone connectors for tears, dryness, or deformation. Inspect the mating surfaces on the throttle body and filter housing for dirt or debris that could prevent a good seal.
5. Clean and Reassemble: Clean all mating surfaces with a rag and isopropyl alcohol. If the connectors are in good shape, you can reassemble. Ensure the connectors are fully seated on both the tube and the mating flange before tightening clamps.
6. Proper Clamp Tightening: This is critical. Tighten hose clamps securely but do not overtighten, as this can warp the connector or tube. Use a screwdriver or nut driver and tighten until snug, then give about a quarter-turn more. Clamps should be positioned so the tightening screw is accessible.
7. Reinstall and Test: Reinstall the intake assembly, reconnect the negative battery cable, and start the engine. Let it idle and listen for any remaining hissing. Perform the carburetor cleaner test again around the repaired area to confirm the leak is sealed.
8. Clear Codes and Test Drive: Use your OBD2 scanner to clear any stored trouble codes. Take the truck for a test drive, paying attention to throttle response and idle quality. The "sick" feeling and misfires should be resolved.

As one owner shared after their exhaust upgrade, highlighting the satisfaction of a proper modification: "And I’m so happy with it that I’m now glad I didn’t get a full $2k exhaust." — Banana_rocket_time (source). The principle is the same for intake work—proper installation is key to happiness.

Parts and Tools Needed

• Parts:
  • Replacement Intake Tube/Connector Kit (if cracked). Brand-specific to your aftermarket CAI (e.g., S&B, K&N).
  • Silicone Intake Couplers (Universal, if original connectors are damaged). Ensure correct diameter (common sizes are 3.5", 4").
  • High-Quality Hose Clamps (T-Bolt clamps are superior to worm-gear clamps for performance applications).
  • OEM Intake Manifold Gasket Set (if the leak is determined to be at the manifold). Mopar part numbers vary by engine (e.g., 5.7L Hemi, 3.6L Pentastar).
• Tools:
  • Basic Socket Set and Wrenches (Metric)
  • Screwdrivers (Flathead and Phillips)
  • Torx Bit Set (for certain manifold bolts)
  • OBD2 Scanner
  • Mechanic's Stethoscope
  • Can of Carburetor/Choke Cleaner
  • Isopropyl Alcohol and Clean Rags
  • Fire Extinguisher (for safety during testing)

Real Owner Costs

Costs can vary dramatically based on the root cause and whether you perform the work yourself.

• DIY Fix (Leak at CAI): If the issue is simply a loose clamp or a torn $20 silicone coupler, your cost is essentially zero to $30 for parts. This is the most common resolution based on owner modification stories.
• DIY Fix (Intake Manifold Gasket): A gasket set for the 5.7L Hemi can cost between $80-$150. Add another $50 for fresh coolant and intake cleaner. The repair is labor-intensive but avoids shop rates.
• Professional Repair (Diagnosis & CAI Fix): A shop will typically charge 1 hour of labor for diagnosis and repair ($100-$150/hr), plus any minor parts. Total cost could range from $150 to $300.
• Professional Repair (Intake Manifold Gasket): This is a significant job. Shop labor can be 4-6 hours. With parts and coolant, the total bill can easily range from $800 to $1,500 depending on your location and the shop's labor rate.

The value of a DIY diagnosis cannot be overstated. As an owner wisely advised in a different but related context on maintenance: "Short commutes and lack of load are about the worst things you can do for a HD diesel. Modern diesel’s need to be worked to stay happy." — Th3yca11mej0 (source). Similarly, understanding and promptly fixing intake issues keeps your gas engine happy and prevents more costly damage.

Prevention

Preventing intake leaks revolves around careful modification and regular inspection. If you install an aftermarket cold air intake, follow the instructions meticulously. Double-check all clamps for tightness after the first 100 miles and again periodically. Use high-quality parts from reputable manufacturers; a cheap kit is more likely to have poor-fitting components that leak.

Avoid over-tightening clamps and connectors, as this can cause cracks or warp flanges. During routine engine bay cleaning or oil changes, take a moment to visually inspect the intake tract for cracks, loose connections, or oil seepage. Be mindful of other modifications; as one owner reflected on their priorities, "Beefier tires or a louder exhaust are the last things I’d want on this plush land yacht." — deadbalconytree (source). Sometimes, leaving well-engineered stock systems alone is the best prevention.

What Owners Say

Real experiences from RAM owners:

Success Stories

"Short commutes and lack of load are about the worst things you can do for a HD diesel. Modern diesel’s need to be worked to stay happy." — Th3yca11mej0 (source)

Owner Experiences

"Just wrapped up the first round of mods on the truck & I'm loving the results! ​Added a Tonneau cover & spray-in bedliner, running boards, replaced all 6 factory speakers with Infinity Reference series, S&B CAI & Borla ATAK exhaust." — Marine4Lyf (source)

"​Added a Tonneau cover & spray-in bedliner, running boards, replaced all 6 factory speakers with Infinity Reference series, S&B CAI & Borla ATAK exhaust." — Marine4Lyf (source)

"I would definitely stay away from a diesel if you won’t be towing or really working it. Short commutes and lack of load are about the worst things you can do for a HD diesel." — Th3yca11mej0 (source)

Real Repair Costs

"And I’m so happy with it that I’m now glad I didn’t get a full $2k exhaust. Only off roading so far has been small ripping around a few construction sites and areas I’ve passed that look cool." — Banana_rocket_time (source)

"It was the only thing missing as stock. And I’m so happy with it that I’m now glad I didn’t get a full $2k exhaust." — Banana_rocket_time (source)

"So I think I have settled on this. It has 25k miles, $35k price, and I’ll use it for hauling whatever it is my wife has bought on Facebook Marketplace this week." — bionicpumpkin (source)

FAQ

Q: How long does it take to fix an intake leak? A: The time varies greatly. Diagnosing the leak can take 30 minutes to an hour. Fixing a simple loose clamp on a cold air intake is a 5-minute job. Replacing a torn intake coupler might take 30-60 minutes. A full intake manifold gasket replacement is a major repair that can take a skilled DIYer 4-6 hours, and a shop may book a full day for it.

Q: Can I drive my truck with an intake leak? A: You should avoid driving it more than necessary. A small leak can cause poor performance and reduced fuel economy. A significant leak can lead to severe misfires, which can damage the catalytic converter over time due to unburned fuel. It can also cause the engine to run lean, potentially leading to higher combustion temperatures and engine damage.

Q: Is this a common issue on the 2020 RAM 1500? A: Based on owner discussion data, intake leaks are a noted issue, particularly following aftermarket modifications like cold air intake installations. The stock system is generally robust, but the problem arises when components are altered or replaced without proper attention to sealing. It's a common mod-related issue rather than a widespread factory defect.

Q: DIY vs mechanic – what's recommended? A: For simple leaks at the cold air intake connections, this is a very accessible DIY job requiring basic tools. If you installed the intake yourself, you should be able to troubleshoot it. If the diagnosis points to an intake manifold gasket leak, the repair complexity increases significantly. It involves removing the manifold, which requires disconnecting fuel lines, electrical connectors, and coolant hoses. This job is recommended for experienced DIYers or should be left to a professional mechanic.

Q: Will an intake leak always trigger a check engine light? A: Not always, but it often will. The engine computer is very sensitive to air-fuel ratio deviations. A small leak might only cause a code during certain driving conditions, while a large leak will likely trigger a persistent check engine light with lean codes (P0171/P0174) and/or misfire codes.

Q: I have a Borla exhaust and a CAI. My truck runs poorly. Is it the exhaust? A: It's highly unlikely to be the cat-back exhaust system itself. The exhaust is downstream and does not affect intake air metering. The problem is almost certainly related to the cold air intake installation. Revisit the installation of your CAI, checking every connection from the filter to the throttle body, as this is the most probable source of your drivability issues.