Stumbling chevy tow rig?

426rider · Nov 26, 2006

95 chevy 3500. 454 tbi auto 4x4. When I start it up cold it stumbles a bit then smoothes out. When in park it seems to Idle fine, throttle up fine, but as the revs drop it stumbles a bit then smoothes out again. When I put in drive it stumbles again, worse than in park, and when I step on the gas its stumbles bad, to the point of killing the engine often. When it makes it through the stumble on takeoff it seems to run ok until I stop then it stumbles more and dies sometimes.

Any help on where to start looking for problems. Not showing any codes right now, but I will recheck in the morning to make sure I got the jumper connected right.

Thanks in advance

crash2 · Nov 26, 2006

Remove the distributor cap and check the main shaft in the distributor for any side to side play.....

426rider · Nov 26, 2006

I just replaced distributor the other day. I did have cracked pickup coil wires and when I took old one apart the upper bushing was screwed up. So I got a new one from the chevy dealer(sunset) It seems worse with new distributor though. Will check just incase.

Avanteone · Nov 26, 2006

426rider said:
I just replaced distributor the other day. I did have cracked pickup coil wires and when I took old one apart the upper bushing was screwed up. So I got a new one from the chevy dealer(sunset) It seems worse with new distributor though. Will check just incase.

Did you follow the correct procedure to reset ignition timing?

crash2 · Nov 26, 2006

Thats what I was thinking. And if you got a complete dist. from a dealer it isn't an OEM dist (they do not sell a complete assembly) unless they ordered all the individual parts and assembled it--otherwise its an aftermarket jobie.

GaryTJ · Nov 26, 2006

Weak spark was my first impression too. Probably has the dist off a bit, or worn plugs.

426rider · Nov 26, 2006

Avanteone said:
Did you follow the correct procedure to reset ignition timing?

probably not. looking into it more this morning.

C-It was a whole assembly.

crash2 · Nov 26, 2006

Devon---pull the vacuum hose off the egr and cap it--run around a lil bit with it that way. Don't worry the ses lamp may come on. More than likely the control soloniod is failing and not regulating tyhe vacuum flow to the egr causing it to open more than it should---causing a drop in manifold vacuum causing your prob :;

426rider · Nov 26, 2006

That is starting to sound like it could be my problem thanks will go try that now.

426rider · Nov 26, 2006

Ok well is was a combination of timing off, worn plugs(I planned on replacing them today anyway) and a bit of a vac leak at one of the connections to the MAP sensor. probably from me fubling around back there replacing the dist. Truck seems to be running better than it has in a while.

Who the hell is supposed to know about a tan wire under the dash that needs unplugged to set timing? well I do now.

Thanks guys

Harvester of Sorrow · Nov 27, 2006

426rider said:
Who the hell is supposed to know about a tan wire under the dash that needs unplugged to set timing? well I do now.

I think this is funny too...

While tearing into the 454 TBI harness this weekend with BenW for my project...He held it up (the tan wire) and said "I think you disconnect this one for setting timing...." I probably had the most ****ed up look on my face.