"What are the most common problems with the 1987 Mustang GT's engine?"

Question

Accepted Answer

The 1987 Mustang GT's 5.0L High Output engine has several well-known issues that owners frequently encounter:

**Top 5 Most Common Problems:**

1. **TFI Module Failure** - The Thick Film Ignition module is notorious for heat-related failures, causing stalling, rough running, and complete ignition failure. This is the #1 issue with these cars.

2. **Idle Surge/Rough Idle** - Very common problem caused by:
   - Dirty or failing Idle Air Control (IAC) valve
   - Vacuum leaks in the aging vacuum lines
   - Improper TPS (Throttle Position Sensor) adjustment

3. **Vacuum Leaks** - The 1987 models have extensive vacuum systems that develop leaks over time, causing rough idle, stalling, and poor fuel economy.

4. **Timing Chain Issues** - The factory timing chain and gears wear out, leading to timing noise and potential engine damage if not addressed.

5. **Fuel System Problems** - The 1987 models use early fuel injection that can have:
   - Clogged fuel injectors
   - Failing fuel pressure regulator
   - Dirty mass air flow sensor

**Good News for This Specific Car:**
With only 21,817 miles and being "Original & Highly Original," many of these issues may not have surfaced yet. The low mileage suggests the car hasn't had the typical heat cycling that causes TFI module failures.

**Prevention Tips:**
- Replace the TFI module proactively (they're inexpensive)
- Check all vacuum lines for cracks
- Clean the IAC valve and throttle body
- Consider replacing the timing chain assembly

Would you like me to help you find similar low-mileage Fox-body Mustangs, or do you have questions about inspecting this specific car?

Lot HOC1141: 1987 Ford Mustang GT

Classic cars

Cars for sale

Resources

Lot HOC1141: 1987 Ford Mustang GT

Become a CLASSIC Insider