Engine Running Rich Due to Fuel Leak Inside Intake Manifold on GMC Jimmy

Vehicles using the enhanced vortec V6 engine may be hard to start run poorly and/or use to much fuel due to a fuel leak inside the intake manifold plenum. Commonly this is caused by a leaking fuel pressure regulator or fuel line. The fuel system will need to be pressurized with the upper intake manifold removed in order to determine the exact cause of the leak. Removing the "tuning valve" from the upper intake can allow for limited visual inspection without removing the upper intake manifold.

RepairPal Verified
Average mileage: 172,166 (80,000–338,000)
5 model years affected: 1992, 1993, 1994, 1995, more2001
12 people reported this problem
5 people shared problem details
1994 GMC Jimmy338,000
I used to see I lot black smoke from the exaust, hard to start I opened the intake plenium and I saw one side clean left side and right side dirty. I pull the switch without turning on and that's when I saw the fuel preassigned regulator leaking fuel into the intake
Had to replace pressure regulator.
1994 GMC Jimmy80,000
gas in oil, failed emissions test
I think I have the same issue, waiting to check with a fuel pressure guage
Engine started having rough cold starts and fuel pump could be heard running constantly. Computer started throwing misfire and rich fuel codes. Checked pressure and found that it fell off rapidly with key turned to off. Hour and a half spent under my carport replacing the regulator and it's all fine now.
Related Items:
My 98 engine overheated and I tried to save it. I have a 2000 jimmy 4x4 engine that looks almos...
The intake manifold gasket may develop and external engine oil or coolant leak. In some cases,...
I HAVE A 2001 GMC JIMMY IT IS BURNING REALLY RICH AND ONLY GETS AROUND 6 TO 8 MILES TO A GALLON...
I have an anti-freeze odor when I put heater on. Has been diagnost as a small leak in heater co...

Related Content