2020 Mustang Grinding Noise or Rough Idle? Timing Chain/Belt Fix Guide

How to Fix Timing Chain/Belt Issues

The 2020 Ford Mustang, while a symbol of American muscle, can sometimes face timing chain/belt concerns as it ages. Some owners have encountered issues with the timing components, leading to performance hiccups. As one owner noted, "I was told to watch out for timing chain issues and was told rough idling/buzzing on cold start and idling at stops it will buzz as well."

Symptoms

Owners have reported a range of symptoms that could indicate a timing chain/belt issue. Rough idling is a common complaint, often accompanied by a buzzing sound, especially during cold starts or when idling at stops. This can be disconcerting and may point to a problem within the timing system. The roughness could indicate the chain is stretched, impacting valve timing.

Another symptom reported is a grinding noise. One owner recounted, "Dealer sold it to me saying there is no problems. Next day it grinds at 1.5rpm and today it’s worse and does this at 2k." This type of noise, especially if it worsens with engine speed, is a serious warning sign that should not be ignored. This type of noise could indicate a failing tensioner or guide.

In more severe cases, owners have experienced stalling. This can occur while slowing down at a red light or even at a complete stop. Stalling is a dangerous symptom that indicates the engine is not receiving the correct fuel and air mixture at the correct time.

Beyond these specific symptoms, a general loss of performance can also be a sign of timing issues. While harder to pinpoint, a decrease in power, especially during acceleration or burn outs, could suggest that the engine's valve timing is not optimal. This is because optimal valve timing helps the engine generate more power.

Most Likely Cause

Based on owner reports, a fuel system issue, or an intake leak is the most common root cause of timing-related symptoms in the vehicle. This isn't a direct failure of the timing chain/belt itself, but rather, problems in the fuel delivery or air intake that can mimic timing-related problems. An intake leak could cause the engine to run lean, impacting the stability of the engine and the smooth operation of the timing system. A malfunctioning fuel system can also throw off the air/fuel mixture and cause the engine to run improperly.

How to Diagnose

Diagnosing a fuel system issue or intake leak that's mimicking a timing problem requires a systematic approach.

1. Visual Inspection: Begin by visually inspecting all fuel lines, vacuum hoses, and intake connections for any signs of cracks, leaks, or damage. Pay close attention to areas around the intake manifold and throttle body.
2. Smoke Test: A smoke test can help identify vacuum leaks that are not readily visible. This involves using a machine to pump smoke into the intake system and observing where the smoke escapes.
3. Fuel Pressure Test: Use a fuel pressure gauge to check the fuel pressure at the fuel rail. Compare the reading to the vehicle's specifications. A low fuel pressure could indicate a faulty fuel pump, fuel filter, or fuel pressure regulator.
4. OBD-II Scanner: Connect an OBD-II scanner to the vehicle's diagnostic port and check for any trouble codes related to the fuel system or intake. Codes such as P0171 (System Too Lean, Bank 1) or P0174 (System Too Lean, Bank 2) can provide valuable clues.
5. Listen: Listen closely to the engine while it’s running to identify tapping or slapping noise as the engine RPMs increase.

Tools needed:

• OBD-II scanner
• Fuel pressure gauge
• Smoke machine (optional)
• Basic hand tools (wrenches, screwdrivers)

Step-by-Step Fix

Addressing a fuel system issue or intake leak involves several potential steps, depending on the specific problem identified during diagnosis.

1. Address Fuel System: If the fuel pressure test reveals low pressure, start by replacing the fuel filter. A clogged filter can restrict fuel flow and cause a lean condition. If the problem persists, the fuel pump may be failing and need replacement.
2. Address Intake Leaks: If a vacuum leak is detected, replace any damaged or cracked vacuum hoses. Pay attention to any hoses connected to the intake manifold, throttle body, and PCV valve.
3. Clean the Throttle Body: A dirty throttle body can restrict airflow and cause idling issues. Clean the throttle body with a throttle body cleaner and a clean rag.
4. Inspect Intake Manifold Gaskets: If the intake manifold gaskets are leaking, they will need to be replaced. This is a more involved process that requires removing the intake manifold.
5. Verify Fuel Injectors: Dirty or failing fuel injectors can disrupt the fuel delivery. Consider having the fuel injectors professionally cleaned or replaced.
6. Clear Codes and Test: After making any repairs, clear any trouble codes from the OBD-II system and test the vehicle to ensure the problem has been resolved.

As one owner shared: "Really get to know the thing, it's ins and outs, what it needs, and YOU did it. I've done all these things and more on my car (the timing was fun... sorta." (source)

Parts and Tools Needed

• Fuel filter (check your local parts store)
• Vacuum hoses (various sizes, check your vehicle's specifications)
• Throttle body cleaner (any auto parts store)
• Intake manifold gaskets (check your local parts store)
• Fuel injectors (optional, if needed)
• Basic hand tools (wrenches, screwdrivers, pliers)
• OBD-II scanner
• Fuel pressure gauge
• Smoke machine (optional)

Real Owner Costs

The cost of addressing fuel system or intake leak issues can vary depending on the severity of the problem and whether you choose to DIY or take it to a professional mechanic.

• Fuel Filter Replacement (DIY): A fuel filter typically costs between $20 and $50. The replacement is relatively simple and can be done in under an hour. Total cost: $20-$50.
• Vacuum Hose Replacement (DIY): Vacuum hoses are inexpensive, typically costing a few dollars each. Replacing them is also relatively easy, but it may take some time to locate and replace all the damaged hoses. Total cost: $10-$30.
• Throttle Body Cleaning (DIY): A can of throttle body cleaner costs around $10. The cleaning process takes about 30 minutes. Total cost: $10.
• Intake Manifold Gasket Replacement (DIY): This is a more involved repair. Intake manifold gaskets can cost between $30 and $100. The replacement process can take several hours.
• Fuel Injector Replacement (Professional): Replacing fuel injectors is typically best left to a professional. The cost of fuel injectors can vary widely, from $50 to $200 each. Labor costs can add another $200 to $500, depending on the number of injectors being replaced. Total cost: $400 - $1300.

DIY: $30 - $100 Professional: $400 - $1300+

Prevention

Preventing fuel system or intake leak issues in your vehicle involves regular maintenance and attention to detail.

• Regular Fuel Filter Replacement: Replace the fuel filter according to the manufacturer's recommended intervals. This helps ensure that the fuel system is receiving clean fuel and operating at optimal pressure.
• Inspect Vacuum Hoses Regularly: Check the vacuum hoses for any signs of cracks, leaks, or damage. Replace any damaged hoses promptly.
• Keep the Throttle Body Clean: Clean the throttle body periodically to prevent carbon buildup and ensure smooth airflow.
• Use High-Quality Fuel: Use high-quality fuel from reputable gas stations. This can help prevent fuel system deposits and keep the engine running smoothly.

What Owners Say

Real experiences from FORD owners:

Owner Experiences

"Really get to know the thing, it's ins and outs, what it needs, and YOU did it. I've done all these things and more on my car (the timing was fun... sorta." — houtex727 (source)

"I think it's part of having an old (yeesh, is a 20 year old car 'old' now?... my poor baby...) car is working on it. Really get to know the thing, it's ins and outs, what it needs, and YOU did it." — houtex727 (source)

"that 4.6 has a lot of the same issues that the 5.4 has, theres a lot of reliability issues after 100k, you’re probably gonna be replacing a lot of timing chains, also triple check the lug studs on the rear wheels because they love to break off and are a pain in the butt to replace." — colbygraves97 (source)

Lessons Learned

⚠️ "I still don’t know much about cars tho lol, but learning as I go. I was told to watch out for timing chain issues and was told rough idling/buzzing on cold start and idling at stops it will buzz as well." — Particular_Lead9272 (source)

⚠️ "I was told to watch out for timing chain issues and was told rough idling/buzzing on cold start and idling at stops it will buzz as well. It’s also stalled once while slowing down at a red light and also at a complete stop at a stop sign." — Particular_Lead9272 (source)

FAQ

Q: How long does it take to fix fuel system/intake leak issues?

A: The repair time can vary depending on the complexity of the problem. Simple repairs like replacing a fuel filter or vacuum hose can be done in under an hour. More involved repairs like replacing the intake manifold gaskets or fuel injectors can take several hours or even a full day.

Q: Can I drive with fuel system/intake leak issues?

A: Driving with fuel system or intake leak issues can be risky. A lean condition can cause the engine to overheat and potentially damage engine components. It's best to address the problem as soon as possible to avoid further damage.

Q: Is this a common issue on this vehicle?

A: While not the most common issue, fuel system and intake leak problems can occur on the vehicle, especially as it ages. Regular maintenance and attention to detail can help prevent these issues.

Q: DIY vs mechanic - what's recommended?

A: Simple repairs like replacing the fuel filter, vacuum hoses, or cleaning the throttle body can be done by a confident DIYer. More complex repairs like replacing the intake manifold gaskets or fuel injectors are often best left to a professional mechanic. As one owner put it, "I still don’t know much about cars tho lol, but learning as I go" (source). Know your limitations and don't hesitate to seek professional help when needed. It depends on your skill level and the tools you have available. If you're uncomfortable working on the fuel system, it's best to take it to a mechanic. Also, double check lug studs on the rear wheels as they love to break off.