Mechanics

ROUGH IDLE

1998 Chevrolet Blazer

I have a blazer that runs roughly, I dont know what the problem is. I have replaced everything that has to do with the engine running, new wires, new plugs, new egr valve, new ignition switch and module, new timing chain, new distributor, new fuel pump, new fuel filter, just about everything that has to do with the vehicle running is new and I dont know what else it could be, we got a new computer but we took the chip out of the old one and put it in the new one but I dont know if that would even matter but anyways I would appreciate any help with why vehicle has a very rough idle
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Broncos38
October 8, 2013.




Do you do any basic testing before you replaced, anything? I mean a basic tune-up is ok, but, what about trouble codes. Can you even communicate with computer?

Do you think the timing is ok? What about cleaning idle air system?

JDL
Oct 8, 2013.
I think the timing is alright, we made sure we had the mark on the gear line up with the mark on the engine, it might have been a quarter of an inch off but not much, we got a new pcm for it, they said it was already programmed, but we took the chip out of the original one and put it in the new one, I dont really know if that matters or not. My Dad seems to think its the PCM computer but I have my doubts, he knows more about this stuff than I do. It could be the PCM computer

Tiny
Broncos38
Oct 9, 2013.
Does it run ok off idle? If so, maybe a vacuum leak?

The part where you said the timing might be a little off, concerns me. Was the computer new? Hey, I asked about codes? Some of the national brand autostores will check codes for free, or use an obd2 code reader.

JDL
Oct 9, 2013.
Well my dad said the timing was alright and I made sure that what he said was the truth, so I just go on and believed what he said was true you know, the computer is new, but we ordered another one and we are going to take it to Ed Martins and have the program it, they said its already embedded with a chip if this other one doesnt work, hes gonna take the chip out of the new one which is the original chip for the first computer, we are just taking that chip out and putting it in the new one, but like I was saying I dont know if the chip has anything to do with it, my dad told me that it has nothing to do with the engine itself but he said the timing was lined up correctly

Tiny
Broncos38
Oct 9, 2013.
I understand. At the moment, I don't have any other suggestions. Let know what you find.
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JDL
Oct 9, 2013.

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