Skip the auto shop - Our mechanics make house calls

Q: What would make all three plugs on bank to foul out?

asked by on

Truck has a new crate motor with actual miles of only 3500 new plugs wires sensors etc. The truck just started misfiring at cruising speed. It is showing misfire on number two cylinder, I pulled plugs checked all the wires wires are fine. Question is all the plugs on bank to our fouled but all the plugs on bank one look perfect. The truck cranks up fine and holds feel pressure at 55–60. It starts miss firing wants the engine is warmed up and I start cruising down the road. also I checked the EGR valve and did not really see anything wrong with it. I also checked for vacuum leaks and could find none. Thanks for any help or info you might have for me. I also replaced all three CO2 sensors about two weeks after motor was put in .

My car has 156000 miles.
My car has an automatic transmission.

A: From what you've described, you'll ...

From what you've described, you'll need to have the fuel pressure tested to make sure it holds after tuning the key off. If the pressure drops then you may have a leaking fuel pressure regulator. If pressure is okay then test the O2 sensors to make sure they are working and not shorted out. If you need some help with these checks, consider YourMechanic, as one of our mobile experts can come to your home to diagnose the misfiree and help you make the necessary 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

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: rough idle dies at 65 hesatation

Hello. Thanks for writing in about your 2002 Chevrolet Silverado. This can be caused by a number of things. Most of the time this will cause a Check Engine Light to come on if there is a powertrain issue. If...

Q: Engine misfiring

On a modern car such as yours, the Check Engine Light should come on for a misfire. There is a technical service bulletin (TSB) # 11-007 which states the front engine mount can cause vibration and knocking from the engine...

Q: Fuel rail sensor faulty or fuel pressure too high

Hello there, a check engine light for too high of fuel pressure is unusual with your 2009 Audi Q5. There are one 2 possible faults going on. Either the fuel pressure is too high, or the fuel pressure sensor is...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
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.