I have a '97 TA and recently the car has been down on power. It started bucking at random times and threw the SES light. The light went out and came back on flashing, which I took to be a misfire code. We scanned the car and that is the only thing that comes up - multiple random misfire. What can I do to narrow down what is wrong? I know it could be the Opti but before I go that route what else should I be checking? I have a fairly new fuel pump, plugs and wires.

Any help would be appreciated.


Richie

 

any updates?

 

What about your ignition coil?

 

Check the ohm resistance on the plug wires. I keep my wires at less then 3 ohms resistance, but if its over 15 ohm id replace it. the ignition coil could be weak. id upgrade to MSD part number 8226 to eliminate that possibility. Codes like to come up for me when optis goes, but not always.

id bet money on the coil being weak though

 

I was curious about this post because I am experiencing the same exact symptoms. I replaced my Opti to resolve the issue and it has made no difference. I also replaced the plugs and checked the resistance on the plug wires, which are 2 years old w/ less then 15k miles on them.

I actually bought a new GM coil and was going to swap it out and I checked the resistance of the existing original one against mine and they were identical. Is it typical for coils to be weak and have perfect resistance levels?

I decided to try and have the ICM tested at autozone.. at the 1st store the guy used alligator clips instead of the modular plug to test. He said its bad and he looked and they had one in stock.. I asked if he could “test” that one before I bought it to ensure its good.. Well that one tested bad.. I went to another autozone and the guy there could not find the modular plug to test the ICM and said the guy at autozone 1 didn’t know what he was doing.. He seemed quite knowledgeable asked about my symptoms.. He was CERTAIN it was a fuel related issue and wanted to sell me a fuel pressure checking device that they didn’t have in stock anyways.. Said that fuel pressure is typical for misfire issues..

From the parking lot of Autozone 2 I called a good friend who has worked at GM dealers for years to see if he could test my ICM at work if I dropped it off. He said the Dealership did not have a device that would test my issue. He actually stopped over 2 years ago when I had some serious issues after I replaced my plug wires. He quickly found I had crossed two of them and it ran great for a long time. He asked about the symptoms and said he thought it was a faulty plug wire.. I told him I just replaced the OPTI and plugs and actually resistance checked ALL PLUG wires as I plugged them into the OPTI to ensure I had them right.. The resistance matched on all of them. He said resistance checking plug wires is NOT accurate, that under load they can misfire even if the resistance is low.. He suggested I spray the wires down w/ water at night and have someone rev it up in the driveway at night while I look underneath and look for Arcing..

I stopped at Autozone 1 on my way home to see if they could pull my history and see if the wires were lifetime.. They were not they are accell 8.5’s w/ a 90 day warranty. That clerk asked about the symptoms and suggested I replace the Crank sensor..

It’s a stoke 97 SS w/ 72K.. BN opti and plugs, 2 year old wires the fuel pump passed away last year and that was replaced w/ a racetronix.. The car pops when accelerating and is clearly missing and generates a code P0300 in less then 10 miles of being reset… Then the SES starts blinking..

I wanted noting more then to have my ICM to test bad and couldn’t make that happen last night.. I am in a situation where buying new parts to see if they correct the issue is just not an option.. I was going to try the wet down the wire test..

Is it typical for a coil to bench test perfect and perform like crap? Does a fuel pressure test seem in order to diagnose popping and random misfire?

Didn’t mean to hijack your thread Aeroforce1, but was curious to how you were making out and thought our issues where related and made sense to chime in.

 

Not sure where you left off Richie, just wanted to let you know my issue was burnt plug wire. Changed mine tonight and the last one I replaced was burnt at the manifold #7. Hope your issue is resolved..