can anyone give me a few ideas what to check? this only occurs at perating temp and during 30% or less throttle. if i go 50% or even WOT clears right up like there is no problem. feels like the ignition is completely breaking up. also RPM range does not matter. if i stay at part throttle, it will stumble all the way through the entire rpm range.

 

Opti?

 

Opti, the fix all I don't think WOT would be fine if the opti took a crap

O2 sensors are key to getting the air/fuel mixture right during part throttle driving. Also check for any exhaust manifold or vacuum leaks.

 

this happened one time at the beginning of fall. i replaced the coil, and it has been fine until a week ago. the new coil has always had a wierd ticking sound ever since it was installed. the day it started was right after i had flushed my heater core, but i did it at the firewal connections.

 

Sounds like an O2 sensor is failing. Is the SES light on? If so, Auto Zone can read the codes for you if you don't have a scanner.

If you have access to datamaster or any other OBD1 scanning software, you should monitor the O2 sensor MV when at part throttle. They should be fluctuating from around 100mv up to around 950mv.

The reason the car runs fine at WOT is because you are entering PE (power enrichment) mode, which uses the fuel mapping from the PE table and ignores feedback from the O2 sensors.

 

join the club , dont install the bosch o2 sensors. THEY ARE GARBAGE !!! Ihave to get them out of mine now cause it fixed it for a little while and it came back.

 

i should have stated NO SES

 

I had the a low rpm stumble where my car would just fall on it's face. Car had all new ignition system components prior to the trouble. After months of chasing it down, my problem ended up being the Bosch platinum 4s or the MSD 8.5s I put in the car with only a thousand miles on both. I believe the NGK platinums fixed my problem. I changed the MSD wires because they wouldn't route through the factory looms on the passenger side. I had to reroute them under the accessory brackets which pinched the wires pretty severely. I went ahead and replaced them with Taylor Spiro Pros 8mm which fit in the factory looms. Good luck..