I'm having this same sort of issue right now. I scanned my car and my right O2 wasn't getting any voltage so I swapped it out with a brand new one. It still did the same thing. My opti has gone bad before and these are all symptoms of it. I think my opti shat itself again. I'm finding out for sure this week while I'm getting my cam installed.

 

Check your o2 wires maybe you burned one up on those headers

 

Took the car to another mechanic. He assured me that it was ignition related and not a fuel problem, but he couldn't figure out what was wrong. Maybe I'll try someone else next week.

 

try the ICM cooling mod on shoebox's website. I have this problem and will be trying that sometime next week when i get time. Apparently it shows phenominal results, assuming the ICM is the problem.

 

So has anyone fixed their problem yet either?

 

I'm having the same problems and I have tried all of those methods and it still doesn't help. If I let my car sit for an hour after doing it, the car will run fine. So i guess now I'm going to try my MAF and see if that helps. Otherwise, there is nothing else to try.

 

Nope. Believe me, I'll let you guys know when it's fixed.

 

Found out my fuel pump was bad. Its something to check into.

 

All y'all need to check the frequency response of the MAF. Simple 2 minute test with a multimeter that reads frequency. Measure frequency at the yellow wire to ground with engine running. Snap the throttle and see if the response jumps over 7KHz. If not clean and try again. If still lower, replace it.

Unplugging will not always find the problem with the MAF but the test will.

 

My car all the same symptoms as above, longer it heats up the worse it gets with the fuel cutting off until it is pretty much impossible to drive..
The opti is going to be replaced so I'll let you all know if that's the problem.

 

When doing the maf test that speedy suggests, I get 3 khz at cold idle and when I snap the thottle it goes to only 5 khz. Would this be normal since my maf is descreened? Also would using a paperclip pushed thru the weatherpak connector on the yellow wire give an accurate reading since my reading was low or what is a better way to do it?
When I get a missfire when warm, unplugging the maf changes nothing.

 

Its the fuel pump. I just replaced mine, and every probem dissappeared.

 

I replaced mine and still had all my problem

 

I have the same problems as 97BBlackZ, I first replaced fuel pump,fuel filter, plugs, wires, intake elbow w\ new iat, coil, icm, ect sensor, and finally replaced opti and waterpump. The new opti fixed the problem and it ran great in the recent 95 degree heat. I install a moroso cold air intake today and in 10 minutes my car starts to missfire and stall. I scanned it and it has po171 and 174 codes. I put the stock airbox back on but it still runs like crap. Has anyone fixed this yet? I thought I solved it till I put on my new cai.

 

Help this guy out, he has been struggling with this car for a while.

Did you check the Fuel Pressure to see what it is doing? should be at 45psi if it is a strong pump.