My car has just been running worse and worse. Starting months ago from a bogging down anywhere above 2000rpm, to a random stumbling miss that gets worse the longer the car runs. Now it has the above, along with random hard misses, and popping and crackling out of the exhaust if i hold the rpm at the same place. Also, the longer it runs the worse it runs, sometimes to the point where it's almost undrivable after 15-20 minutes of driving. The idle has also recently become erratic, and while sitting in traffic in gear the engine will change idle every few seconds, sometimes up to 1/4 throttle. I have recently replaced the TPS (since it threw a code after getting wet), Injectors, and ICM, which all made absolutely no difference. According to a diagnostic a local mechanic did, I'm not showing any missfires. The opti and wires were replaced less than 30k ago, and the plugs were replaced less than 800 miles ago. I also installed a new ignition coil. It's getting expensive to figure out whats wrong and i'm currently out of money.

Here is a link to a datamaster log for any of you that want to take a look at it, notice the spark advance, and throttle position stay the same while the rpm has peaks and valleys. The o2's are also all over the place. And if you notice, I think even saw a few times where it peaked at 6375rpm(is that not past the rev limiter?) while at 8% on the tps.

TTS Datamaster is free for the first 20 recordings, so please download it at the following link if you think you can help.
http://www.ttspowersystems.com/softw...ta/EE-FULL.ZIP

And my Log at...
http://69.93.44.42/~cam94z28/datamaster/miss.uni

Currently accepting offers on a 94 Z28 "mechanics special" with 132,000 miles.

 

TTT

 

First thing that jumps out at me is that your MAF readings are way too low....you'r showing AFGS readings that are in the high 30s to low 40s on pulls to 6000rpm....they should be in the upper 200 range.

Have you tried unplugging the MAF and running in SD mode?

TPS readings are low also....was this log done befor you replaced it?

Inj DC and pulse width are also low.

 

Thanks for taking a look at it. The log was actually after i replaced the TPS.

I haven't tried running in speed density mode, but i have a feeling it wouldn't run any better. I wasn't in gear during that log, I was idling in park and revving.

I have a new connector spliced into my MAF because one of the wires broke on the original one. I guess I should double check that my connections are solid.

 

If you use "export as .csv", and post the file as a .csv instead of a .uni, anyone can look at the file with Excel. That way they don't have to go through the TTS download hassle just to look at your file.

Is it possible you have your "units" for the MAF set to pounds/minute? That would make sense.

#/min X 7.56 = grams/sec

 

The low numbers may be because you were not under load. Do an actual driving log and let me look at that.

Also if you spliced the MAF harness I highly recommend that you soder those wires together.