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

ntreftz

ntreftz

Too broken to be broke $$
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!
 
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I don't see where you replaced the crankshaft position sensor. The tach dropping to 0 is usually an indicator of a bad CKPS. Might also want to check the harness that goes to it as I believe it also feeds the cam sensor as well. The harness could be chaffed enough to be grounding out causing the interruption of the signal. Might also want to be sure the balancer is good as this also can cause issues.
 
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.
 


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


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.
 
buck531 said:
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.
Click to expand...

fuel pump could be going bad. mine did that tach crap when it was stalling out from it.
 
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.
 
Found a 09 g8 gt with 30k at a dealer

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