Thread: Assittance needed. Misfire, stalling and spurratic rpm gauge. Stupid car!

I've been having issues with my 98 gtp. Mods in signature. Recent parts replaced
- icm
- plugs autolight 606s
- coils
- tps
- flexplate

All installed by me and my friend. The flex was a pita..

Anyways, it started having issues about a year ago, high idle then stalling. I have to 2 foot it everywhere I got to keep it running. I had misfires on 1(52k misfires), 4(32k) 5(400) 3(about 200) and 6 and 2 were minimal 1 or 2. so I replaced the coils, plugs and wires. Still continuing to mis I changed the icm. Still no result. Compression is good. 134-150psi cold check. Sometimes the tach would drop from 2500 to 0 and pop back up like a terrible mis and re-fire. I unplugged the maf and it stopped recording any misfires and ran a tad better but today not so much. Back to the usual spurratic tach and yet no recorded misfires. Any help or suggestions would be really awesome!

New balencer as of a few months ago, but that's a good start. Want to notate that when it drops in rpm rapidly the fuel trims are wonky. At about 1200 rpm it seems like its "hunting" for a trim it likes. Going between -11.6 ltft to +3.6 ltft. Its acting luke it has a vacuum leak, unless its tge intake manifold gaskets leaking i cant find it. When it does the the rpms get a bit of a harmony from 1230rpm to 1300.. It's kind of odd. Also when it drops its not the engine speed that concerns me its like it shuts off briefly and the records withing milliseconds. Would that still be the cps?

She died, and won't start again.. The o2s are reading .6-.5v like its flooded and the ltft is at -4.6
I have no idea where to start.

CPS can have rpm's run wild, bouncing like a vac leak, almost stall, stall, then recover... Had it in my 01' SE, turned out to be a few wires in the harness dried and brittle because it was sitting on the AC Condenser... Found it by checking ignition circuits. Fixed by opening harness, cutting, splicing and whoola, all fixed.

I think Fordman had a good idea. Plus, you mentioned replacing balancer, are you sure the balancer magnet was placed correctly? Did the problem start after new balancer? New or JY balancer? Cleaned the balancer magnet? Lol... Could be quite a few things. Just my thoughts... Good luck

Tach moves when starting, it is running so much fuel itss damn near hydrolocking. The magnet was cleaned, and its a new balencer. The problem started after the flexplate cracked.

Intake gaskets maybe?

you sure the flex is on right? if its not on right it can cause some good vibrations due to being off balance.

No vibrations really, it only seemed to go one way, the crank had an offset bolt and so did the torque converter.

you pulled the engine or the tranny to swap the flex?

maybe you pulled or chafed a wire some how?

I'm hoping that's the issue but it was doing this before the swap

well that adds a new layer of suck to the equation lol

I'm having a VERY similar issue with the poverty car. Ran fine all summer and fall. Just in the past 3 weeks when I give it almost any more than 20% throttle it bucks REALLY bad like a misfire. Twice the tach shot to 7k (motor didnt go that high) and it stalled. I Haven't hooked my laptop up to it to scan it (that comes Saturday).

I do have an extra ICM harness I could try. I can't remember if I did anything to the car before this started happening.

Originally Posted by buck531

I'm having a VERY similar issue with the poverty car. Ran fine all summer and fall. Just in the past 3 weeks when I give it almost any more than 20% throttle it bucks REALLY bad like a misfire. Twice the tach shot to 7k (motor didnt go that high) and it stalled. I Haven't hooked my laptop up to it to scan it (that comes Saturday).

I do have an extra ICM harness I could try. I can't remember if I did anything to the car before this started happening.

fuel pump could be going bad. mine did that tach crap when it was stalling out from it.

Originally Posted by ScottyDoggs

fuel pump could be going bad. mine did that tach crap when it was stalling out from it.

Sounds like a misfire though? I dunno. Good call on the fuel pump. Stock 180k L36 pump lol. Surprised it lasted 5-6 passes at the track.

mine would buck and sputter, then come back to life or die. if it died i left the key to run, hit the shrader valve and nothing came out the rail.....i knew wtf was up asap then.

after a while of this crap it did toss icm codes and a crank code. swapped it all and it did it again, did the harness, that was damaged, and it did it again lol new pump, solid since.

Awesome. This will give me a reason to get a new pump and injectors = Corn. .

Also, if I rev it in park or neutral it's perfectly fine. Only when there's a load on the trans.

Getting 60psi on prime and 47 running

Looked at a focus St and it was badda$$

Found a 09 g8 gt with 30k at a dealer