This is a 92 gmc suburban 5.7L with 298,000 on it. Truck already needed intake gaskets so I replaced intake gaskets, tb gasket, egr gasket, egr solenoid, t stat, full tune up (plugs, wires, cap, rotor), fuel filter and air filter. Even after all of that when its cold out the truck runs very rough for the first few minutes until warm (almost like the egr is stuck open but its not). It also sometimes drops all power but stays running when cruising about 40mph and has no throttle response doesn't matter if cold or hot (not sure if these two problems are related, I'm betting they are just want it fixed)..
Check the idle air control on the throttle body it is on when the engine is first started stays on until the engine is warmed up.
SOURCE: s10 pickup after warming up truck starts missing
You might have computer problems.
Does the check engine light come on when it starts to miss?
SOURCE: 95 GMC Jimmy 4.3l W vin rough idle
My problem was solved when I repaired my 4 wd activation dash switch. The switch was contacting on 2WD & 4HI at the same time. The front differential activation is vacuum activated possibly creating a tug of war that didn't actually engage it but drained off vacuum from the engine? A theory at best but stumbbled across it because I knew the switch wasn't working properly I repaired it and low and behold rough idle disappeared and all is good for 3 weeks running.
SOURCE: 87 chevy truck with TBI idles too fast
Spray the intake with carb cleaner to find the vacuum leak. Check where the EGR mounts and the throttle body gasket sense you had both off.
SOURCE: Shakes while idling and sometimes stalls.
check for minor vacuum leak and map sensor,pcv,egr valve
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Ok now the truck runs really rich on start up for about 5 minutes, enough that you can smell the fuel. Also got out on the highway today and was cruising about 65 and then it starrted to stumble and when I went to try and give it more gas it died.
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