1991 5.7 TBI runs rough when cold

[df2x4]

my truck is a 95, cant just hook a scanner to it.

You can I believe, it's just a little more difficult to find a scanner compatible with OBD1 vehicles. A GM Tech 2 or clone should do any of these trucks from '91 on up. There are other solutions involving a laptop and cable but I'm not too familiar with those.

 

[Schurkey]

my truck is a 95, cant just hook a scanner to it. and i unplugged the EST wire and it ran considerably worse. so i am picking up a timing light today to start with that.

My scan tool connects to, and communicates with GM vehicles back to 1981.

OF COURSE you can "hook a scanner to it" if you bought a decent scan tool.

Yes, you should buy a timing light and verify base timing. Running worse with the wire disconnected is pretty normal, the truck needs the base timing set at TDC ("0"), but would normally run with computer-added timing advance.

 

[MrPink]

You can I believe, it's just a little more difficult to find a scanner compatible with OBD1 vehicles. A GM Tech 2 or clone should do any of these trucks from '91 on up. There are other solutions involving a laptop and cable but I'm not too familiar with those.

Yeah I dont think i will get to the point of needing the laptop, and i only have the 1 obd1 vehicle all others are newer. so i dont think i'd want to buy a scanner for one vehicle. if it ****** me off enough i have a 5.3L LS i will swap in and convert it to OBD-2 with the 96 Body harness i have.