gmc jimmy

I know the bare minimum about cars and haven't owned a GMC before. So bare with me. I just bought a 94 Jimmy, engines clean, car is immaculate, said it was "sitting for 5 months it had a dead battery, and that the timing was a little off but that was it" 🙄 "Otherwise is a strong running...

I've got a 2000 jimmy sle. 4.3l v6 vortec 4x4 drive. I'm looking to put flow master super 44's on there, but whenever i input my vehicle, it says the exhaust is not compatible with the vehicle. thing is, i used to have a 98 chevy s10, and when i plug that in, it says the exhaust is compatible...

I've replaced the sensors, distributors, cap, wires, plugs, cam sensor, crank sensor, as far as electrical goes. I don't know if the problem is electrical or not. When I try to start it it fires but will not start. The computer is fine, as far as I know, but I don't know if it might a rehab...

so i bought a 93 gmc jimmy ran it about 200 miles and when i started to stop it stalled out i started it and it has a bad idol up and down up and down.. so i took it to a machanic and he cleaned the EGR valve out and pit it back in.. so im driving it two days later and same thing happens again...