Had an issue with the truck hesitating at around 45 to 55mph. Also had no movement on the truck until it warmed up, This happened if you let it sit for a couple days. Thought to be tranny related I took it to Tim Moye trannys in Lutz Fl, he did an oil, filter change, and added some additive, and said the tranny is in perfect shape. He drove the truck and experienced my problem and said engine related, like it needs a tune up. If you drive the truck at around 45 to 55 and get on it, as you let off and resume those speeds the problem is more significant. On hard acceleration I have a lot of black smoke, none at idle, none while daily driving, on acceleration only. Recently I replaced all vac lines due to crack and replaced the wastegate solenoid. Ive got 25" all over except for at the wastegate, where before and after these changes Ive only got 15". Dont know if all this is related just looking for the answer. By the way, new pmd(2000 miles), fuel filter, and i believe a recent(10000 mile) injection pump. The gentlemen I bought the truck from had all the major stuff before I bought it. He said during the life of the truck he had about 2 or 3 pumps due to problems from the factory. Any help would be wonderful!!
pete

What is the number on the IP tag? Should read DS4.......5???

We need the ? numbers

If I read it correctly the numbers are as follows D5 D24831 S5288

anyone got an idea?:help:

Are there any codes stored in the ECM?

When you say there is 'no movement until the truck warms up' do you mean that on a cold start you can put the truck in gear and when you step on the pedal the engine just revs and nothing else happens?

If that's the case you may want to get a second opinion on the trans....

X2 on the "no movement" with Chris.
Don

no codes in the ecm, its a 94 so im doing the paperclip trick, will that work? As far as movement, none, step on the gas and truck just revs with the load of the truck not moving. Tranny guy reffered to it as something, cant remember, problem is no oil gets through the tranny until it warms up, said 85% of the time a new filter and oil change takes care of it. Only way to find out if it did is to not drive the truck for a couple of days, kinda hard seeing its a daily driver. But ill see what I can do.

That sounds like the drain-back problem from the converter. Had that with a T350 trans a few years ago. I'd find a new trans guy.
Don

Yes - use the paperclip trick....

I am having my doubts that it is engine related...sounds like internal trans issues....

Drain back, thats exactly what he said. The guy I went to is real reputable and has the cleanest shop with every cert and newspaper giving him praise for being the best but also great work. Being a shop owner myself I was really impressed with his people and his place. I know all that doensnt mean squat but it helps when choosing someone. He said 85% of the time drain back can be fixed with a fluid change and filter. Whats the ways you guys fix it and does this happen on the 4l80's?

A few times in the past when I put the truck in reverse it would load up and want to go without any throttle. Thought I would share this, to me, I thought it was the converter.

The paper clip trick is good for some codes. You need a decent reader to get into the transmission circuit for codes and/or solenoid action as well as system voltage. These 4L80's are really reliable transmissions and do take a beating.

I think the drain-back is inside the converter, IIRC we changed the converter to fix it - that was several years ago.
Don

Took the truck for a second opinion. Gentlemen immediatetly bashes the other guy, until I said Tim Moye trannys did it. He backed off quickly and said Tims the best, definetly know his stuff, must be an engine problem like he said. So he took it for a drive and he agreed, not the tranny but engine related. So I called my mechanic, he suggested starting with fuel pressure, lines, injectors, lift pump, maybe the ip, and if all those checks pass, maybe I should begin to get worried. So Im off to work to figure it out.

I'm still not understanding how when you say that the engine just revs and the truck doesn't move is engine related....can you get the engine to redline with the trans in gear?

to reproduce that problem the truck has to sit for a couple days. Im going to try to let it sit this weekend to see if the fluid change fixed it. I think I originally had two problems and one has now been solved, I believe the second problem is engine related.

My blazer did the same thing, if you drove it every day it was fine. If it sat for more than a day or 2 it wouldn't move until it ran for 2-3 minutes. I agree you have 2 problems, conveter and the miss.
Don

So I let the truck sit over the weekend and whalah! no drain back problems. talked to the mechanic, and hes convinced fuel pressure is the cause. so my next step is tackling that.