Q: Rough idle, missing, almost dies when in gear, shaking violently when driving in low speeds

asked by on

Husband did tune up. Plugs, egr valve, cops, fuel filter, etc. Noticed a misfire right away. Had codes pulled, cop 2 was misfiring so replaced it again. But now it has continued to get worse. Found a hose that was rotted, replaced it. He's cleaned throttle body, MAF sensor, injectors. We've literally tried EVERYTHING!! Any suggestion on what we might be missing?

My car has 139000 miles.
My car has an automatic transmission.

Hi, thanks for writing in. I’d be happy to provide my insight. I recommend you have the engine checked for vacuum leaks, or and check if carbon is clogging the EGR valve. If you still cannot find the reason the engine is running bad, then my advice is to have a mechanic come out and diagnose the problem for you. I have seen carbon breaking loose and holding valves open, and also I’ve also seen coils for the plugs not firing or shorting out, causing misfires. Try moving the coil in the misfiring cylinder to a firing cylinder to see if misfire moves with the coil. If so, replace the bad coil and coil boot.

If you would like help, consider having an expert automotive technician from YourMechanic come to your home or office to inspect and diagnose this issue for you, and make or suggest any repairs as needed.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 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

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. Rough idle, missing, almost dies when in gear, shaking violently when driving in low speeds

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: Alternator not charging

Hello. If the alternator is not charging the battery then it may be failing. There are other problems that can occur such as bad battery connections or a failing battery cable. If the car has the wrong battery in it...

Q: Rough idle after replacing Mass Air Flow Sensor - trouble codes P0171 and P0102

The P0171 refers to a possible lack of fuel pressure, a leak in the intake air system, or a possible vacuum leak. The P0102 also leans towards a leak in the intake air system. It is possible that there is...

Q: My transmission is "clunking"

Sometimes a transmission is serviced when it is on the border of starting a problem. This will cause the transmission problem to show itself in a short time. The new fluid will clean out areas of wear, and the thicker...

Related articles

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...
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...
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.