Skip the auto shop - Our mechanics make house calls

Q: RPM drops while driving

asked by on

I recently did some work on my truck, new fuel filter, oil, oil filter, valve cover gaskets, spark plug tube gaskets, intake mainfold gaskets, MAF sensor cleaned, throttle body cleaned, and cleaned some dust and dirt off the air filter. About a week ago it started to drop rpm while I drive once i get to speed and the rpms come to the normal 1500-1600. They drop down to 1000-1100 and i can feel it aswell as watch the rpm gauge drop. I am getting no DTC codes or check engine light. I am stuck and have no idea what to check next. Maybe PCV valve? Thanks for any help!

My car has 170000 miles.
My car has an automatic transmission.

A: Hello, from what you describe it appears th...

Hello, from what you describe it appears that your vehicle may be experiencing some sort of engine performance issue, perhaps a misfire. Usually misfires will cause a drop in rpm, as well as shaking or engine vibrations. This can be caused by many things. If you recently worked on the vehicle, I would go back and double check that all sensors and connectors are properly secured and in good condition. Specifically any that you may have worked on. The next thing I would do is check for vacuum leaks, perhaps through damaged hoses or faulty gaskets. The PCV valve may also cause similar symptoms, if it gets stuck in the open position. If it remains stuck open the engine will have a vacuum leak, which can cause misfires. I would start by double checking all the components you worked on, and then going from there.

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 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

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!

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: WHAT TO FIX?

The problem sounds like the engine is not running on all the cylinders. You should have the spark plugs and wires checked to see if the plug wires were put on new distributor cam correctly. Then replace the spark plugs...

Q: Car is giving codes P0032 and P0038 and stalls

Hi there. Diagnoses needs to be performed. As you already know, replacing components can be expensive and time consuming without resolution. The P0032 and P0038 codes could be the result of a blown fuse, a wiring issue from the PDC...

Q: I am leaking antifreeze

Hi, thanks for your question. I'd be happy to help. You can make a note of where you notice the leak, then have a mechanic come to pressurize the cooling system and isolate the leak for you. The water pump...

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...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.