engine stumbling lost ideas.

[Vortec Lover]

o2 sensors

EDIT: you say you replaced all the sensors... never mind then

 

[TylerZ281500]

02, map, nss, egr deleted(didnt affect it), knock sensor plug.

 

[GMstrong]

check the timing,hows the injector spray?how many miles is on it?

 

[jcoatswo]

I would recommend replacing the TPS. I replaced mine because I was having to let off the throttle sometimes to get the truck to shift from 1st and 2nd. I put a new one in and I've noticed a HUGE difference in the entire performance of the truck. It drove OKish before but replacing the sensor made a word of difference.

Also I know you said that the plug wires weren't touching anything but wires, especially on our vehicles, can heat up around the exhaust manifolds, heads, intake, etc. and ruin the casing on the plug wires. Electricity travels on the outside of metal (wires in this case). I've learned from doing car audio installs, soldering and what not, that if you get any kind of wire too hot the casing and melt around the wire and suck itself into the wire just as solder does. In turn this is affecting the integrity of the wire since you are smothering the wire in a non conductive material. I would suggest doing the old water spray bottle on the plug wires at night time just to make sure you have no arcing.

Last thing, before I replaced them my 94 had some old plug wires on it, whenever it would rain or it was humid I would get a nasty power loss in the engine. I thought it was a bad intake gasket. Also the wires were ran sloppy, touching metal parts of the engine, which for a low quality plug wire is enough to make them short in the first place. I cleaned the routing up and I was still having the issue. It turned out to be that my plug wires got dry rotted, probably from heating up and cooling multiple times a day for x amount of years, they were arcing when there was a conductor (water in this case since I eliminated the grounding possibility) anywhere near them.

 

[TylerZ281500]

tps replaced, timing at 0*, injectors spray as they should, actual mileage unknown. the wires are on a wire loom spererator and everything, brand new ones and even with the old wires it still did this.

 

[jcoatswo]

When you replaced the egr did you clean the ports in the intake that lead to it? When I did my intake these ports were completely blocked. I had to soak the intake in a parts cleaner then I had to make a homemade flexible drill bit to clean the ports which were pretty much still blocked. You can make one out or a coat hanger if you flatten and sharpen one end, kind of making it look like a spade or speed bore drill bit. What I did was take one of these http://www.homedepot.com/p/t/202505...505170&storeId=10051&R=202505170#.UToHExzktVU and cut off both ends and sharpen the "drilling" end on a bench grinder.

 

[TylerZ281500]

tbi has been removed cleaned shaved etc. the pod is new out of my friends camaro and that car ran great with the same setup.

 

[jcoatswo]

Not in the TBI. The EGR ports inside the intake manifold under where the EGR mounts to the intake.

 

[TylerZ281500]

brand new edelbrock tbi manifold. very clean, i inspected it.

 

[jcoatswo]

Did you hook up your electric fans yet? If so are they on all the time or activated by a temp sensor? Or if you are still running the mechanical fan is the clutch locked? Just a thought because if the trans fluid is already cold and staying cold longer than it should by means of something like a constantly running fan the truck will feel sluggish until the fluid is warm. Also have you added any additives to the trans like Lucas? I put some Lucas in mine a couple of weeks ago and the truck shifted funny for about a week while it was working the super thick fluid into the trans and the Michigan winter didn't help much. I may be talking out of my ass but its worth a shot, usually a fix for a problem that's tripping you up is something stupid.