Skip the auto shop - Our mechanics make house calls

Q: Car shakes when idling

asked by on

My car shakes at idle, and a cold start is getting a p0300 code misfire.

A: I know these vehicle symptoms all too well....

I know these vehicle symptoms all too well. If your GMC Yukon runs better after it has warmed up then it is likely that it is experiencing a vacuum leak in the intake manifold gaskets. It is not uncommon for these gaskets to fail as they are sandwiched between the cylinder head and the intake manifold and because of their location, they are exposed to extreme heat. When these parts start to fail, unmetered air enters the combustion chamber through the leaks, in turn, disturbing the air/fuel mixture your computer is trying to achieve. However to be 100% certain that this is indeed the problem, I recommend enlisting the assistance of a certified mechanic to come by and inspect your car’s shaking issue. They will have the experience and tools necessary to confirm if this is the problem as well as make the repairs to restore your GMC to running smooth again.

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: Random misfires

Hello. There are several possibilities that could explain why you are having this problem. One possibility is that you could have one or more faulty fuel injectors, or the fuel injector wiring is damaged. Another possibility is...

Q: Transmission keeps going out - 2007 GMC Yukon XL 1500

Hello. It sounds like you do not have a transmission problem at all. I have seen this same vehicle have electrical issues which will cause the vehicle to stop shifting correctly. If the transmission continues to go out, I would...

Q: Valve lash is good,check rod bearings. Engine taps under load.doesnt tap when in neutral and revving engine. Timing off 1 tooth?

Hello. Check intake vacuum at idle to "guess" as to the status of the timing. If below factory spec., for example if as low as 15 inches or so (vac. gauge reading), you might be off a tooth. Really, the...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...