Mopar Guy New To Gmc! Please Help Im Lost.

[579]

i just picked up a 1994 gmc sierra. its a half ton 2wd standard cab. my buddy (whom i bought it from) rebuilt the 4.3 v6 four years ago and it ran like a raped ape! problem is between the bigger cam, headers, flowmasters, accel coil blah blah blah the computer needed to be reprogrammed for the motor to run right and after the computer work it did. it has the 4l60e by the way. now all of the sudden it starts running like it's always in a high gear (sluggish out of the hole) like it has a stall converter in it or something and it's sputtereing, backfiring, stalling and over all just plain sucks! did the reprogramming vanish? i can't find anyone to work on the computer again and at the 700 bucks he paid four years ago to have it reprogrammed i'm not even sure if the computer is the problem. any suggestions on any of this? a new motor is 1300.00! i'd try to rebuild this one stock but i don't know whats been done to the heads or any thing else. how about a motor and tranny with no computer controls? does that exist? is there a certain motor/tranny combo that will drop right in and bolt up? man my 83 dodge sounds alot more appealing right now. thanks, brandon

[Wingnut]

From the brief description, it sounds more like you might have dropped a gear (tranny shot).

 

You might get more replies over in LD...So I'll move this over there for you.