1987 GMC Suburban Runs ruff andSTALLS

KEN4D

MEMBER
1987 GMC SUBURBAN

Engine Performance problem
1987 GMC Suburban V8 Two Wheel Drive Automatic

Just purchased an 87 Sierra 1500 350 ran fine 4 two weeks then startedrunning ruff and stalling @ operating Temp hooked a scanner to it got codes 33 (map sense High)and 45( Exhaust Rich) I replased map solenoid and map sensor this seemed to make things worse now it runs bad (sputtering like only on 3 or 4 cylnders and dies everytime immediatly and picked up a new prob its hard starting now I have to pump and hold gas pedal to start any suggegstion would be appreciated

3 Replies

PEAR69

MECHANIC
1,482 POSTS

Check or just replace the coolant temperature sensor (CTS). Test the o2 sensors. Is this a fuel injected or carburated engine? Check the fuel filter. Check for intake leaks.

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Sunday, September 20th, 2009 AT 4:57 AM

KEN4D

MEMBER
2 POSTS

It IS CARB. WITH THE THE THROTTLE BODY iREPLACED THE COOLANT TEMP NO DIFFERANCE IN PERFORMANCE RE-TIMED ENGINE SEEMS TO BE RUNNING SMOOTHER BUT STILL DIES WHEN HOT REPLACED EGR VALVE AN TPS RUNS REAL GOOD BUT STILL DIES WHEN HOT RPLACED THE DIAPHRAM IN THROTTLE BODY ALL CODES WERE GONE NOW LOW TPS IS COMING UPAND STILL RUNNING VERY RICH VOLT AT TPS KOEO IS.2 KOER.2 THIS IS READING FROM SCANNER NOT AT THE SENSOR NO VOLT INCREASE WITH TROTTLE MOVEMENT