Hey all, new here & I need HEELLLPPP (runs ROUGH!!)

meimg · 09-27-2006, 01:33 AM

I've got a 90 GMC/1500. I'm Original owner. 175,000 mi. Never a problem till now. Recently I replaced plugs, rotor and cap. Last week I put gas in it and immediatly it began to run rough under acceleration. Of course I figure gas. So I drained tanked checked flow and pressure of pump. All good. I've replaced the fuel filter, pulled the pressure regulator to check diaphram. All good. So I think I've eliminated a fuel problem.???? I had an after market prom in brain but I just put the original back in.(who knows) I just put new plug wires (ACCEL), coil (MSD), rechecked plug gap, checked cap 4 cracks. On &on &on &on&on. All for not. Last nite I rechecked timing (0) I have checked the resistance on the IAC and it is out of range. NO codes during all of this. IS IT THE IAC? I really don't want to start replacing parts. With no codes this has been a _ _ _ _ _ _ - _ _ _ _ _ _ nitemare. I'm beating my head against the wall and it's starting to give me X-cedrin headache #. They don't have a # 4 this 1. Thanks to all in advance who are sick enough to help try and figure this out.

bobcat5544 · 09-27-2006, 02:36 AM

Pull the spark plugs look at them if you can take a pic of them and post it here just by looking at the plugs can tell you where to start

mudseeker · 09-27-2006, 05:44 AM

when did you put the old prom back in? i'm willing to bet your computer needs to relearn it's self or taken to dealership to be reprogramed.

scottie · 09-27-2006, 07:33 AM

maybe the TBI?

49er · 09-27-2006, 07:59 AM

Greetings,
I have a '95 chev,ext cab, short bed, with 350,
all auto, and about 160, 000 miles.
About 150, 000 mi there was some start of rough running.

As it turned out one of the head gaskets was about to blow out,
or started to blow.
When it finally went, there was water, (antifreeze) in
the oil.
My opinion is to check compression,

if there is any doubt, don't mess with trying to "FIX" the problem.

Bite the bullet, fork out for a new "crate" engine, or
after market motor from PAW or Summit Racing.

175,000 miles is a good job for a motor.

How many years?????????????

then junk out or rebuild your present motor
at your leisure.

just another perspective.
kent

meimg · 09-27-2006, 08:00 AM

OK here we go.
Bobcat I will get you some pics of plugs and post either late tonite or in morning. They've only been in about a month max. I took them out yestertday, checked the gap. The electrodes are like new and the porcelin is still white.
Mudseeker I'll call a dealer tommorrow and check. It does have the dual prom setup.
Scottie could u be a little more specific. I did pull the regulator and checked it.
Again thanks guys. I'll keep in touch. And it's nice to see some sick puppies who like to beat themselves up to help the other man or woman. Hopefully I'll be able to return the favors in the future.

09-27-2006, 01:33 AM	#1
meimg Junior Member Join Date: Sep 2006 Posts: 2	Hey all, new here & I need HEELLLPPP (runs ROUGH!!) I've got a 90 GMC/1500. I'm Original owner. 175,000 mi. Never a problem till now. Recently I replaced plugs, rotor and cap. Last week I put gas in it and immediatly it began to run rough under acceleration. Of course I figure gas. So I drained tanked checked flow and pressure of pump. All good. I've replaced the fuel filter, pulled the pressure regulator to check diaphram. All good. So I think I've eliminated a fuel problem.???? I had an after market prom in brain but I just put the original back in.(who knows) I just put new plug wires (ACCEL), coil (MSD), rechecked plug gap, checked cap 4 cracks. On &on &on &on&on. All for not. Last nite I rechecked timing (0) I have checked the resistance on the IAC and it is out of range. NO codes during all of this. IS IT THE IAC? I really don't want to start replacing parts. With no codes this has been a _ _ _ _ _ _ - _ _ _ _ _ _ nitemare. I'm beating my head against the wall and it's starting to give me X-cedrin headache #. They don't have a # 4 this 1. Thanks to all in advance who are sick enough to help try and figure this out.

09-27-2006, 05:44 AM	#3
mudseeker Senior Moderator Join Date: Feb 2006 Location: michigan Posts: 6,374	when did you put the old prom back in? i'm willing to bet your computer needs to relearn it's self or taken to dealership to be reprogramed. __________________ i'd rather be hunting

09-27-2006, 07:33 AM	#4
scottie Senior Member Join Date: Jan 2006 Location: South Florida (Palm Beach), originally from south of BOSTON Posts: 644	maybe the TBI? __________________ im a straight shooter with upper management written all over me

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09-27-2006, 02:36 AM	#2
bobcat5544 Full Member Join Date: Sep 2006 Location: St. Louis, MO Posts: 27	Pull the spark plugs look at them if you can take a pic of them and post it here just by looking at the plugs can tell you where to start

09-27-2006, 07:59 AM	#5
49er Full Member Join Date: Sep 2006 Location: Veneta Oregon Posts: 25	Greetings, I have a '95 chev,ext cab, short bed, with 350, all auto, and about 160, 000 miles. About 150, 000 mi there was some start of rough running. As it turned out one of the head gaskets was about to blow out, or started to blow. When it finally went, there was water, (antifreeze) in the oil. My opinion is to check compression, if there is any doubt, don't mess with trying to "FIX" the problem. Bite the bullet, fork out for a new "crate" engine, or after market motor from PAW or Summit Racing. 175,000 miles is a good job for a motor. How many years????????????? then junk out or rebuild your present motor at your leisure. just another perspective. kent

09-27-2006, 08:00 AM	#6
meimg Junior Member Join Date: Sep 2006 Posts: 2	OK here we go. Bobcat I will get you some pics of plugs and post either late tonite or in morning. They've only been in about a month max. I took them out yestertday, checked the gap. The electrodes are like new and the porcelin is still white. Mudseeker I'll call a dealer tommorrow and check. It does have the dual prom setup. Scottie could u be a little more specific. I did pull the regulator and checked it. Again thanks guys. I'll keep in touch. And it's nice to see some sick puppies who like to beat themselves up to help the other man or woman. Hopefully I'll be able to return the favors in the future.