2001 Chevy Blazer cycled 4 missfire

FAST_BLUE_CAR

MEMBER
2001 CHEVROLET BLAZER
6 CYL
4WD
AUTOMATIC
98,981 MILES

I have a cycled 4 misfire and I had change all the plugs and wires, cap, rotor, coil, fuel fitter, pcv value, ignition control module, and all six fuel injector's.
And I still have a cycled 4 misfire. What could be worng still?

Tuesday, March 2nd, 2010 AT 9:05 PM

3 Replies

OBXAUTOMEDIC

MECHANIC
3,711 POSTS

Hello,

After each repair did you have the codes cleared? If not then it usually takes from 50 - 100 key starts or about 500 - 1k miles to clear. Also DO NOT disconnect the Battery to try and reset to codes you can fry the computer. Would recommend going by your local part store and asking them to clear the codes for you.

.

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Tuesday, March 2nd, 2010 AT 9:47 PM

FAST_BLUE_CAR

MEMBER
7 POSTS

I went and got the codes clear. And the ligth came back on saying po304 cycle 4 missfire.

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Tuesday, March 2nd, 2010 AT 10:02 PM

OBXAUTOMEDIC

MECHANIC
3,711 POSTS

Ok, what you will need to check the Wiring Harness on that Cylinder, and in order to do that you will need a Noid Light. You can check with your local rental store or even the parts store.

If the wiring harness test good then you will need to check the Cylinder Compression.

If compression checks good you will need to check for Vacuum Leaks.

Also, has the engine been overheating? Have you had to add coolant or checked the coolant for signs of oil. Also check the oil for signs of coolant.

If either has the above then the most likely culprit is a blown head gasket.

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Wednesday, March 3rd, 2010 AT 10:34 AM