Well I've done almost a complete tune up trying to cure this problem, with no luck.

Everytime I take off from a stop, the truck begins to stumble at 1800 rpms and returns to normal after it shifts into 2nd gear. Once in 2nd gear and above, it drives normal.

I've replaced the spark plugs and wires, PCV, and Crankcase breather as well as the breather tube. I also cleaned the intake with 1/2 can of SeaFoam, which spit out TONS of smoke, so I know the intake was quite dirty. I also put a bottle of fuel injector cleaner in a half tank, but only drove about 50 miles so far. The oil is fresh and level, and the tranny oil is gorgeous and level.

My truck only has 99K miles. Please help!!! Ideas? Fuel Filter? Distro cap and rotor? ign coil? crank sensor? What's this thing that I've read about this plenum problem?

 

Are you getting any codes. Check engine light. I'm having the same problems and have done all the same stuff you have with a misfire on 8. I'm getting a compression check done monday to see if i have a burnt valve. I even rented a tool from autozone to plug in to the injector connectors that lights up to see if the wiring is right. and it was. I swapped injectors around today as well and it didn't fix it. If you aren't getting a check engine light you might take it to autozone and see if they can run a scanner on it. It might throw a code even though your light isn't on.

 

No code yet. I will pull the codes anyways, there are a number of DTC that don't grow on the MIL, especially since we have 96's, the first year OBDII was introduced.

 

Ok so I replaced the distro cap and rotor, still same problem. I can't find the EGR valve, I thought it would be behind the engine next to the distro. Maybe I don't have one on the 96. Any other suggestions? I really hope it's not the tranny.

 

Had the same problem changed the wires, cap, and button and fixed the issue. Mine didnt throw a code either. Make sure you put some electrical grease on button, and cap points.

 

I also thought it was my tranny at the time, change the spark plugs while you are there.

 

IMPORTANT UPDATE: When shifting the column shifter into 1st gear and then accelarating from a complete stop, the engine DOES NOT STUMBLE at those same RPM's. So, this would exclude the transmission from the picture. It also makes me suspect that a valve maybe open when driven in Drive.

 

the egr valve is behind the pass. valve cover....IAC possibly?

 

I was thinking the IAC. Actually, my thought were "what valve opens during normal driving in D, and doesn't open when shifted manually into 1st?" I'm going to re-read those operation sections in the service manual today. Shoot, I'll be happy to replace all those sensors anyways lol.