Skip the auto shop - Our mechanics make house calls

Q: Engine idles rough and jumps between 500 and 1200RPM when shift from Drive to Reverse; Check engine light on

asked by on

The engine seems fine most of the time but it idles rough and occasionally jumps between 500 and 1200 rpm when I shift to drive or reverse. When I throttle and it hits 4000 rpm, the 'Check Engine Light' starts flashing. Can you give me advice as to what to do to fix all of this?

A: You may have a couple of separate issues: ...

You may have a couple of separate issues:

  • The flashing Check Engine Light under heavy load is most likely an ignition system misfire. This could be something like a coil pack or worn spark plugs. These engines are known for going through coil packs so that would be my first guess.

  • The rough idle could be related, but it sounds more like a vacuum leak or possibly a faulty idle air control valve (IAC).

The first step is to retrieve the diagnostic trouble codes for your Check Engine Light which serve as a starting point for any further diagnosis. I suggest you have a trained professional, such as one from YourMechanic, diagnose your vehicle firsthand.

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: Idle problems with car.

This problem of idling high is most likely a problem with the idle air control valve stuck or a vacuum leak in the intake system of the engine. I would recommend having your high idle speed inspected by a mechanic,...

Q: Random gear shifting

Hello, it sounds as if you have a faulty transmission pressure control solenoid or contaminated fluid. Also, the electronic gear shift sensor under your gear shift could be compromised if something has spilled on it. I suggest that you have a...

Q: Lights work, but car won't start.

I would need more information to determine the problem. If you hear a clicking noise but the engine wont turn over, then your battery may not have enough charge or may have a bad connection. Test the battery, if the...

Related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
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...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.