Worse now... car does not rev at all passed 3500 RPM

[mr_wizard]

In my previous thread I posted how the car would hesitate really bad (zerothread/175091) at 3300 RPM and then get to 5500 RPM and just not make it passed. The motor runs excellent up until that point, but now it won't even make it passed 3500 RPM. It's almost like a rev limiter... the tach just bounces up and down. Few people suggested the MAFS, I replaced that and got nothing. Others suggested TPS, I just got threw replacing that and it still does exact same thing. What else could be causing it?

[mr_wizard]

WHOA wtf, I was just driving the car and it accelerated all the way to lik 5500 RPM without a problem!?!? Once it hit there it backfired and I stopped... I was sort of afraid to do it again, but I wanted to try again to see if it was still doing it and I tried and it still was sort of hesitant, but not as bad as it was. So it reved really well until 5500 RPM once, then I tried again and it wasn't as good but better than it was a few hours ago. It actually got so bad I couldn't get over 3k RPM today. Then this.

[rogoman]

Maybe it's something as simple as a dirty fuel filter. Also it might be a marginal fuel pump; check the ground connection and the voltage at the pump.

[JeromeS13]

Check your codes from your ECU. If you get a code 21, I'm willing to bet its the distributor.

[mr_wizard]

If the ECU is throwing codes, wouldn't the check engine light come on?

[JeromeS13]

Not necessarily.

[mr_wizard]

This varies on whether the car is warmed up or not and how much gas your giving it. Once I get to 3500RPM I can floor it and make it passed but the motor struggles. ALSO, very important, I disconnected the tps and it actually ran better than with it connected. What the hell? No matter where I move the TPS it acts the same so I'm clueless. The TPS and MAFS are new. It's got to be something other than the TPS right?

This whole incedent happened pretty much all of a sudden. I was driving the car pretty hard... not REAL hard but pretty hard and it started hesitating real bad kind of spontaneously in random RPM spots. Then it got gradually worse where I couldn't rev at all over a certain RPM.

EDIT: I finally got a friend to help me with testing the TPS with a multimeter and we adjusted to exactly where it should be, which was where I had it originally. Anyway, I still have to problem and the TPS checks out fine.
Modified by mr_wizard at 5:34 PM 5/26/2006

[mr_wizard]

Another update: If I hit 3500 RPM in 1st gear the engine completely shuts out and doesn't even try to accelerate passed, if i'm in 2nd or higher it will try and spudder passed that mark.

[JeromeS13]

Did you check your ECU for codes yet?

[mr_wizard]

I've actually been looking around for the process on how to do that. Is it somewhere here on nico?

OK nevermind, I found it in the FAQ. I'll try and do this soon.

[Burnsey]

i posted on one of your previous threads ... but I was wondering if you've checked ur vac lines? ... like with a vac gauge reader. I have the same problem and its come down to a vac leak.

[mr_wizard]

Yes, in fact I replaced all the vacuum lines. I found the problem today, long story short it was bad grounding. The symptoms of bad grounding from what I've been reading sounded too much like mine so I double checked everything, tightened, etc... and the car runs awesome now. Thanks for your help all.

[Burnsey]

what ground was messed up on ur's if ya don't mind sharin'?

[mr_wizard]

it was one of the two on the side of the valve cover next to the exhaust header. They were both loose, so I tightened them and the car ran fine after that. The braided one could be loose in the plastic connector, just make sure it's connecting with the body. This is a common problem from what I read.