Skip the auto shop - Our mechanics make house calls

Q: Won't run when warmed up

asked by on

I have a 08 Mustang GT, when its cold no issue .as it warms up it wont take gas, and idles real choppy in the 300-500 rpm range, I get no codes on anything, I have replaced the fuel pump and filter, cleaned the MAF, and T/B, replaced the throttle position sensor Fuel pressure sensor,throttle motor does work when its not running, I have tried the stock tune still no difference,plugs have been replaced 850 miles ago, Its not the gas filled other car at same place 1/2 after later and its fine

My car has 10210 miles.
My car has an automatic transmission.

A: Hi there. It looks like you have inspected ...

Hi there. It looks like you have inspected most of the common culprits of a choppy running engine. However, when the vehicle gets hot and has running issues, it’s commonly caused by the EGR valve or EGR valve temperature solenoid. As the engine gets warm, the exhaust gas recirculation valve can become stuck, leading to an lean engine condition, which typically lowers the RPM as you’ve indicated. Check this component, clean it, and see if that clears up your problems. If not, feel free to contact one of our professional mechanics to see if they can inspect the choppy engine issue and find the source of the problem.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: When the gas is pressed, the RPM increases, can't accelerate

From what you are describing with the RPMs going high and the vehicle not moving, it sounds like you have a transmission that is not shifting or is slipping. There is a technical bulletin that may stop the flare and...

Q: Engine light flashing intermittently

This may be related to a faulty or dirty mass air flow sensor. The mass air flow sensor is a unit in the intake system that monitors air intake as it is mixed with fuel prior to being injected into...

Q: Bad fuel regulator

You can drive it with the vacuum line off of the pressure regulator if it helps your engine run better. I thing the problem is not the regulator but a problem with clogged injectors or low fuel pressure from a...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...