QuestionExperienced misfire / dropped cylinder on two brief occassions before becoming a major problem. Now engine will start cold, idle and rev with no problem, until reaching running temperature, then experience flooding causing engine to stall when trying to increase revs. Motor will occasionally rev above this point (1000-1500rpm) but it is difficult to get it there - mostly causing engine to flood and then not start. Spark plugs very wet need removing and cleaning to restart. What I have done to try and fix this problem: Change spark plugs and leads, replace distributor and coil, checked airflow meter, temperature sensors at front of motor, airflow idle sensor rear of motor, ECM checked, looked for vaccuum leaks, fuel pump pressure checked, injectors replaced, when tested injector pulse duration seemed long and continues to do so. The vehicle was using more fuel leading up to the problem, but unsure whether this has anything to do with it. Basically engine runs perfectly until reaching a running temperature. Does drop idle speed post revving and will not hold speed to go into drive. Please help, we have not driven this vehicle for two months and is becomming a real headache. Any reference material and testing values would much appreciated.
AnswerHi Shane,
This is a difficult problem. All fingers point to coil initially, however, the coil was replaced. I'd check the amplifier module on the distributor. How did you check the ECM? Are there any CHECK ENGINE codes triggered?
Here's something else I found that might help:
Remove the idle air control valve and housing located at the right rear of the intake plenum. Remove the valve from the housing. Clean the openings on the housing paying attention to the seating area for the idle air control valve and its' plunger. Install the valve back into the housing and install back on the plenum. Making sure that all gaskets are good. Start the engine, check operation.
Check the base idle. Must be done on a fully warmed engine. Turn off all accessory loads. Connect a tachometer. (Dash one not accurate enough). Clamp off the hose between the throttle housing and the idle speed control housing. The speed should be 525 +or- 25rpm. If not, remove the plug on the throttle housing and adjust the bypass screw until correct speed is attained. Replace the plug.
Shane, this is a tough one. My guess, based on my '95 problems I've had, is the spark amplifier module.
Best of luck,
JohnMc
NB: You'll have to be careful with all that flooding...fuel and your cats don't mix.
