i have a 2002 chevy blazer 4.3 4x4. just bought it and the computer is reading random misfire it does not start good and has little miss in it when idleing. i have replaced the plugs, plug wires, distributor cap & button, fuel filter and colant temp control. same as it was BUT when i did the distributor cap and button the first two starts it started good but now itsback to the way it was if any ideas PLEASE let me know thanks.

 

Could be a bad 02 sensor. I replaced 1 in bank 1 and it ran rough after awhile. I cleaned it up and replaced the other two. Goddamn that was an expensive day.

 

Your O2 sensors (well for 95) are $23 and $28 (due been looking at that as my issue for rough idel and radom miss).

But I would also take a can of Carb Cleaner and lightly mist around the intake. The intake is known for issues. Also check your vac lines. If they feel hard (cooked) or spungy (rotted) replace. They should be soft and firm, andleave no marks on your fingers when you roll them or pinch them.

How many miles?
When you got it was it an "AS IS" or did it come with a warranty?
How well do you know/trust the place you got it from?
Exhaust wet or dry? (let it idel for a few min and look at the ground below your tail pipe)
If wet put a peice of paper under the spot and what color is it?
Coolent color (Dexcool orange/rust/mud or Green)?

 

ok i change it and its still the same any other opinions???

 

If you have done all the checks and everything checks out, then run it to your local Checker / Auto Zone / ect.. and have them code scan it for free. Come back with the codes due to it might be the PCM or coil.

Might want to veiw threw the TBS list for 2002 Blazers also. There is almost a full page plus.

But having the codes will help a lot.