Skip the auto shop - Our mechanics make house calls

Q: Why is my pickup running rough?

asked by on

Changed plugs, wires, cap, rotor, and coil, also treated fuel tank and changed fuel filter 3 times to eliminate contamination but the vehicle is still running poorly.
My car has a manual transmission.

Hey there. You should take a fuel sample in a clear glass container, and then if you put the container in a freezer, it will separate the water from the fuel and you will see if you have a lot of water in the fuel.

If there is water present, then you will need to remove the fuel water contamination. If there is no water and gas is not contaminated with anything then you will need to have the engine computer tested for running codes to see if the EGR valve is stuck open causing the rough running engine.

If the EGR is stuck open, it will cause a rough idle to mid throttle but run good at higher RPM’s. If the EGR is not stuck, then the fuel injectors would need to be checked for flow causing one or more cylinders to run too lean from previous fuel contamination. If this is the case, then you may need to remove and have the injectors cleaned or replace them with new ones. For a precise diagnosis, consider YourMechanic, as a certified technician can come to your home or office to inspect the rough running problem and follow through with repairs.

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!
  1. Home
  2. Questions
  3. Why is my pickup running rough?

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: Fan runs when car is off. Overheats when idling for a 3-minute period

Hey there. This can be caused by a number of things such as low coolant levels, a faulty thermostat, or a failing coolant fan switch. As you may know, the coolant fan switch helps to maintain the proper coolant temperature...

Q: Trucks starts up but have to give gas to keep running then dies starts up a second time then it will stay running.

It sounds like you may have a dirty or failing idle air control valve. The idle air control valve monitors the air intake as it is mixed with fuel prior to being injected into the engine at low speeds and...

Q: can i change the mirror on 2011 ford f 150 to a power and heated mirror

Unfortunately, I believe the wiring harness is different on the higher end trucks for the mirrors. It is because of this that I do not believe the power heated mirrors will be compatable. The only way to know for sure...

Related articles

How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
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...
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.