Mechanics

WANT TO BE ABLE TO FIX MY #1 CYLINDER THAT IS MISS-FIRING. MY OBD READER IS GIVING CODE P0301.

2004 Chevrolet Impala • 75,000 miles

A year ago I changed my upper and lower intake/head gaskets on my car(thank god for Haynes). In the last 6 months I changed my belt, the water pump, and the breaks. When I changed my breaks a code for Cylinder 1 started popping up and now stays on all the time P0301. The spark plug is clean but missing the spark piece(appears broken) I have put a new spark plug in but the same code popped up. I took the oil cap off to check the vacuum and idle dropped and went rough when I did that. Not sure where to check Vacuum on Intake though. There does not appear to be any anti-freeze leaking which there was lots of right before I initially replaced the Head Gaskets, thermostat etc. I have read that it could be a fuel injector causing the misfire on the specific cylinder or worse. Any hints or ways to rule things out? The head gasket replacement was the first car repair I have ever done since than I have done everything on it and only in the last month has there been a problem but no fluids or loss of coolant. Just the engine symbol and the code. Help me please.

signed,
frustrated Chevy Impala owner
Avatar
Impala pain
December 5, 2011.



Before you do any work, check the compression in the #1 cylinder. Something broke the plug and may have caused damage to the cylinder causing it to miss.

What is the best way to do that?

Tiny
Impala pain
Dec 5, 2011.
Use a compression gauge to determine the ctaul compression of no.1 cylinder-should be 10% tolerance from the other cylinders-Are the plugs OEM parts-maybe too long of reach-worn plug

Rasmataz
Dec 5, 2011.
When I changed the head gaskets I changed all the plugs and it was a champion I have now put Bosch in. The original plugs were acdelco. I have noticed that certain parts have to be acdelco ie: thermostat, serpentine belt tensioner all have to be acdelco. U think I should put acdelco plugs in? Would it make a difference in plugs?

Tiny
Impala pain
Dec 5, 2011.
Have you checked compression?

No I will check compression next

Tiny
Impala pain
Dec 5, 2011.
Let me know what you find.

CONCERN HERE IS THE BROKEN PLUG

SEVERAL THINGS COULD CAUSE IT, HERE'S JUST A FEW

1) BROKEN DURING CARELESS INSTALLATION

2) WRONG PLUG (INCORRECT APPLICATION), TOO LONG, MECHANICALLY DAMAGED BY ENGINE

3) BURNED OFF, COMBUSTION ISSUES

4) MECHANICAL PROBLEM W/ ENGINE BROKE IT

MANY PLACES (SHOPS) HAVE CAMERAS THEY CAN PUT IN THE PLUG HOLE AND LOOK FOR DAMAGE

SOUNDS LIKE YOU LIKE "DIY"----ME TOO!

THE COMPRESSION TEST MAY TELL SOMETHING TOO

THE MEDIC

Tiny
CJ MEDEVAC
Dec 5, 2011.
First off let me address the sparkplug issue
-im an idiot that just threw it in my tool box and than all my tools on top after I first pulled it. ( Thanks to my wife for pointing that out. So I have access to the Compression Test kit but a mechanic down the street told me to change the coil and wire and see if that fixes the code. I took the plug into a mechanic and he said it was to clean to suggest any damage done by the motor.

I am going to do the Comp. Test though just to make sure.
No harm no foul.

Happy to report that I change the coil, the wire, the just replaced spark-plug (no damage) am the code has been cleared and has3 not returned after a week of driving which should be more than enough time to reset the cylinder misfire code if it was not fixed

Tiny
Impala pain
Dec 13, 2011.
That is good news. I'm glad you got it fixed.