I cannot figure out what is wrong with my blazer. its a 1994 full size sport edition with a 350TBI engine.The truck will ALMOSTaccelerate just fine from a stop in 1st gear but the second it shifts into second, it starts bucking and stumblingreally badif I stay in the throttle. The buckingalmost feeled controlled by something since it does itat a prefect interval. The only way to stop it is if I either back off the throttle or bury the the pedal into the floor board for wide open throttle. The truck revs all the way to 5 grand nice and smooth when it is in park. Its just when it hits second gear and higher. It makes it really hard to merge onto a highway. As I mentioned earlier, the truck accelerates ALMOST perfect from a stop. I said this because 5 times out of 10, the truck will almost not go anywhere when I push the gas pedal, it will rev up a little bit and inch foward,its like someone is holding it back with a chain, then, all of a sudden it just goes and I dont give anymore gas then I originally did. I thought it was just me since I just bought this truck. I then greased up the gas pedal and checked the throttle cable and it all looks fine. Not sure if these two problems are related but its really getting my $ss already. What gives here.

I have done the basic tune up stuff. Someone local had mentioned the EGR valve but wouldnt it do it all the time then. This does it weather the truck is cold or warm. I know the transmission in this truck has electronics in it. Could it be something with the ECm for the tranny? I gotta get this work out before I go back towork. Any ideas guys

 

No check engine light on?
I'd get it checked for any engine or trans codes stored, present and history.
There are so many possibilities that I'd hate to even start guessing and have you replace parts that are still ok.

If you left it in 1st gear (just to test) would it buck if you tried to load it the same as the load in 2nd gear?

 

The truck will not do it for the first few minutes of driving if the temp is cold. I might get 3 miles before she starts acting up. Now the truck feels slugglish to go from a stop so I end up giving it more gas. She will slowlyaccelerate as I give it more gas but then BAM, she just takes off like I hit the nitrous switch or something. its like the truck fixes itself and now it is catching up to where the throttle is on the engine. Then it shifts into second and starts bucking like a champ. I can only stop it by letting off the gas or burying the pedal to the floor. its starting to get bad goinginto overdrive as well. it just feels real slugglish, like I am towing a 30,000lb trailer or something. I have to give it WOTfor the truck togo. And she does go when its at WOT so I know the engine healthy.

I jst get the feeling that its either th TPS sensor or something electical in the transmission