Hi, I am not experienced, and inquiring about my son's 1990 silverado c1500 2wd. He recently got his transmission rebuilt, and had front end ailentment work done. When he first got it back and drove up hill it would jerk or hesitate a little. He thought maybe it was having trouble shifting, and took it back to the shop. They said his tranmission was fine, and changed his fuel filter. The truck is doing the same thing and more often now. Any advice on where to start is appreciated. They truck has 185K miles, had a new exhaust put in about two years ago.
He had an error code about the EGR valve. Would that cause this?
(His vacuum pressure seems to be fine when the problem happens). Like mentioned, I am not experienced, but mechanically inclined and have a background in electronics. Thank you.

 

is it an automatic transmission? does the transmission downshift when hesitating?

 

Yes, the EGR would do that. It doesn't sound like a tranny issue to me either, it sounds like the engine is bogging down. Which would be caused by a lack of fuel (most likely), air (less likely), or bad spark (even less likely). Fuel filter actually sounds like a good place to start. Fuel pump is a possibility, injectors are a possibility, EGR is a possibility, clogged cat(s) are a possibility, dirty spark plugs are a possibility. Quite a few others to, but I would check those first.

 

Thank you very much for the information wmiller. We will try the EGR, plugs and wires. Jimmydow1, the truck has an automatic transmission and isn't shifting down. The CAT is about 2-3 yrs old.

 

the transmission in that truck is a TH400? if so there is a solenoid for the downshift. there should be a switch connected to the accelorator pedal. make sure that it is connected by a wire to the drivers side of the transmission. I have seen this get missed once or twice after a trans rebuild or replacement.

 

There is a lockup solenoid for the torque converter on this one.

The EGR may need to be cleaned as opposed to replaced.

 

Hi Everyone, I am finally back to give an update. I ordered an exact fit AC Delco replacement EGR valve and my son installed it today. His truck is still having the same symptom. He also replaced his air filter, as it was very dirty. His next step is changing his sprak plugs and wires. Any other comments from you guys is appreciated. Thank you.

 

My truck (same as this one) was doing the same thing. Cap,rotor,and wires fixed it. I had replaced the plugs shortly before.
Just for clarification this truck has the 700 R4 trans.

 

Hi Old Wrench. Thank you for the information. Yes, my son's truck has a 700 R4 trans. The next step is we will replace the wires, and spark plugs, then the cap and rotor. ALSO one other thing for you guys. When my son replaced the EGR valve, the hose broke (it cracked because of age). He bought a piece of hose and made a replacement. It seems okay, tight fit, and I think a good seal. The hose he got was more rubbery . (that's all they had). The original one was harder and seemed pre-formed. My questions are is do you think what he did is okay, and do you know where to get a stock replacement of that hose?? ...I'd kind of want to keep stock type parts in there right? Thanks again for all the help!

 

As long as it isn't so soft it collapses from the vacum it should be OK. Original parts are always available from your local dealer.