Skip the auto shop - Our mechanics make house calls

Q: Misfire on cylinder 4

asked by on

Hi, 1997 Chevy K1500 5.7L V8 here with a misfire on cylinder 4. I've replaced distributor cap, rotor, wires and spark plugs and nothing improved. Spark is good. Changed out the spider injector and used a "pop-it" light to check that a signal is being sent into the spider injectors. All is good. O2 sensors are new. Both catalytic converters are 2 years old. What gives?

My car has 190000 miles.
My car has an automatic transmission.

If both fuel and ignition are good, then it may be a mechanical issue with cylinder #4. A compression test may be a route to take. Considering the age and mileage, a worn intake or exhaust valve, or possibly valve seats can be allowing compression to leak past and cause a misfire. It can also be a "sticking or lazy" valve lifter. If the #4 valves are not opening/closing in proper time, this can also cause a misfire.

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: How do I program the power windows?

In order for the express feature to work, the power windows will need to be programmed whenever your car gets a new battery, or whenever the current battery becomes disconnected or recharged. Program the windows with these easy steps: ...

Q: Car sputtering when I let off gas pedal

It sounds like you have a fuel-to-air ratio issue. Anything from the idle air control valve to the oxygen sensor may have a malfunction. Diagnosis would be required before changing parts. YourMechanic can send a qualified technician out to your...

Q: My truck is running sluggish

Hi there, thanks for writing in. If the engine had non-fouler plugs in it then you need to do a compression test. If the engine is worn then it will need these plugs and may not be able to produce...

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...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
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...