Questions and Answers

Jimmy Is Stalling Q. Hi Vincent, I have a problem with my 1987 full-size GMC Jimmy. It has a 5.7 Litre engine with 230,000 km showing. It's equipped with throttle body fuel injection, automatic transmission, power steering, air conditioning and cruise control.

The problem is it stalls at idle when the engine is under any kind of load, i.e.. idling in drive with your foot on the brake or idling while you turn the steering wheel fully to one side or the other. It will idle forever in park and there is no problem restarting the engine after it stalls. I can keep the engine running by adding a little gas to the accelerator but turning up the idle a little doesn't seem to help .The computer is flashing a code 33 when I check but the "check engine light" is intermittent.

I have done quite a bit of troubleshooting on this problem to no avail and even taken it to a licensed garage. Here are some of the things that I have done:

• Completed a full tune up consisting of plugs, wires, distributor cap, rotor button, and fuel filter.
• Changed the idle air control valve and cleaned the housing.
• Replaced the Electronic Control Module and Prom.
• Cleaned and checked ECM ground.
• Replaced MAP sensor.
• Replaced TPS sensor.
• Replaced coolant temperature sensor.
• Replaced coil.
• Checked and rechecked for a vacuum leak.
• Unplugged the torque converter control relay (in hope).

Then I brought the Jimmy to a so called licensed mechanic and here is what he told me he did for a mere fee of $300.00 Canadian.

• Checked for a vacuum leak.
• Checked fuel pressure.
• Checked sensors for proper voltage readings to ECM.
• Replaced distributor with old distributor.
• Replaced fuel injectors with old injectors along with pressure regulator.

I'm not to confident about the mechanic, but I'm assuming that he did what he said he did for troubleshooting purposes.

So Vincent I guess my next step is to the dealership for a quoted $89.95 per hour unless you can help me with something I have overlooked. Any help would be appreciated.

Thanks,
John

A. I have seen this problem before and it turned out being the distributor. I know they had problems on these year engines loosing grounds through the distributor housing. You may be able to diagnose this yourself. Get it to do it. Then unplug the 4 wire harness to the distributor. If it won't stall it's in the distributor. This harness is the computer controlled timing portion.

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