I've been having problems with my engine misfiring/stumbling. I had a MAF sensor code so I got a working MAF sensor. The code's off and I still have a misfire. No other codes are present in the car and I have no SES light showing.

I got the car scanned and it's randomly misfiring on cylinders 1, 2, and 4. The misfire numbers were going anywhere from 6 times to 22 times per 100 cycles. The car seems to run fine under 2500 RPM but above that, it really starts to bog down and it feels like the engine is fighting to make power. If I get into the gas hard, it goes from idle, stumbles from ~2500-~4000 rpm and seems to get better after that. The guy that scanned the car says he believes the opti-spark is starting to fail.

It also has a hard time maintaining an idle. It will sit at ~1000 rpm then it will drop to ~750 and then jump up to ~1200 before backing off to ~1000 again, then it will keep doing that.

One other thing that he noticed is that when the engine starts to drop RPM, the computer goes offline from the scanner. When it pops back up the comes back online. As soon as it drops again it goes offline. Any ideas guys? I'd hate to spend all that money on a new opti and it not be the problem. Thanks in advance.

 

I had ignition issues, and blindly chased the opti. It turned out to be a coil that was weak and not dead. (it still gave good spark, but not enough).

I would start with your wires, and make sure none are arcing just for peace of mind. I would check to make sure they are plugged into the opti vice versa correctly. I would then go and purchase a coil and swap it in to check. (If that does not fix it return it.) Only then I would then point at the opti.

It always made me wonder how long my original opti would have lasted had i not pulled it. I think the opti is better than its rep, but a piece to blame when things dont go right a lot of the time.

Checking ignition from LEAST $$$$$ to GREATEST $$$$$$$ is the only way to check it. Saves headaches and work. I felt like a tard after tearing into the opti project and putting it back together, only to not fix the problem.

OBTW if looking at the opti dont forget to look at the opti harness.

 

Thank you for the response. I will check the wires, but I'm pretty sure they're all good. They're brand new (~2000 miles) Taylor OTVC's and I made sure they weren't touching the headers or anything. I'll look tonight to see if they're arcing. I know they're plugged into the opti correctly because I checked about a dozen times when I was making the wires. I'll give the coil a shot. Thanks for the suggestion. I agree that the opti does sometimes get an unfair rap. I try not to jump to conclusions on it.

 

Well I ran the car tonight and looked for arcing wires but didn't see anything. I did notice something else though. I saw a blinking red LED and realized that I have my O2 sims plugged in. I had the computer retuned and had the sensors programmed out. Could having them programmed out and still having the sims plugged in and operating be causing any problems? I completely forgot they were down there.

 

I really doubt it. Hey what kind of coil do you have out of curiosity?

 

 

Problem solved. Anymore questions?

 

It's most likely the stock original coil.

Ya think it'll work? Where do I pour it in?

Now THERE's a suggestion worth looking into.

 

Well I replaced the coil and while it's not quite as bad, I can still tell the engine is misfiring. I'm assuming it's not as bad because the coil is new vs. being ~10 years and 125k miles old. Do you guys think it's the opti now? I'll replace it if it is, but if that doesn't do it, I'm taking Heather's suggestion and loading it up with dynamite.

 

I had the same issues. I used OPTIKLEEN and it worked like a champ. My optispark was optisparking great. lol.

But seriously it may be the opti from what i read. But dont take my word on it. I never had to mess around with an opti, knock on wood.

 

check your opti harness now. They have been known to fudge up sometimes.

 

I'll check it when I get home this afternoon. In the meantime, any other suggestions you guys might have are greatly appreciated.