4.3 idle ruff

[gtmud]

I have a 91 chevy w/158,000 mls with a strong 4.3w/TBI. My problem is that at idle the truck runs erratic, doesn't stall but sounds like it might. I have recently changed timing gears w/chain, installed a/c delco plugs, r/r wires, cap,rotor, all filters(gas,air). I thought maybe the harm. balancer had slipped, but the timing is dead on. Running Castrol syn-blend 10w-40 oil. Also after dong the T/chain I have an oil leak that won't go away, replaced oil pan gasket, and frnt seal. Other than that it runs great, good accel., and average 18-20 mpg.

[fishtoday925]

sounds like she is running like a champ. I have a 91 blazer with the 4.3 and it is running rough to. I have only relpaced the cap, rotor, wires, and plugs so far and that hasn't helped. tThe next thing i am going to do is take my throtle body apart and clean and rebuild it. I have talked to a few guys and thats what they suggested to do next so i will give it a shot and let you know. Also that is pritty good between 18-20 mpg. Mine is only getting 13-15 , it sucks any tips for that, i have used some fuel injector cleaner and have cleaned my intake with seafoam.

[racericky]

Hay man i work at a auto shop and we had that same problem many times specialy with 92 Astro 4.3 same engine and that problems that we had was the EGR stuck open and the valve springs (that will give you rough idle but normal off idle, with ok power) start with the EGR take it of and plug bouth ports then start engine if it continues its because it have weak valve springs keep me posted to what happend

[racericky]

Hay man i work at a auto shop and we had that same problem many times specialy with 92 Astro 4.3 same engine and that problems that we had was the EGR stuck open and the valve springs (that will give you rough idle but normal off idle, with ok power) start with the EGR take it of and plug bouth ports then start engine if it continues its because it have weak valve springs keep me posted to what happend