I have a 2000 GTP, it has 168,000 miles and I am trying to diagnose this issue. It runs great until the supercharger kicks in, then it misses and pops until you let out of the throttle. I have been told it was an injector, so I put new 35# injectors in, someone else suggested vacuum issues, new vacuum lines installed. What next? I have heard it could be a fuel pump issue, but it runs fine until the blower kicks in. Catalytic converter clogged maybe? Any help would be appreciated, this is my 1st supercharged 3.8 and I love it, I just want to get it running right.
2000 GTP 168,000 miles. Stumbles/misses when supercharger kicks in...Help Please
- Thread starter viper1day
- Start date
Fivefingerdeathpunch
New member
You didnt mention if you have done spark plugs and wires, or if you have even pulled the spark plugs.
If it misfires and pops that bad it must be flashing the check engine light, and the will toss a code to tell you what cylinders it might be.
If it misfires and pops that bad it must be flashing the check engine light, and the will toss a code to tell you what cylinders it might be.
buickman104
New member
If you can get your hands on an OBDII scanner then you can check Long term fuel trims ans if they are locked at 16.4+ then have a big vacuum leak. If they range -5 to +5 then you are in decent shape with your vacuum system.
99GT2dr
New member
I'd bet money on plugs/wires. Pull the 02 sensor out (remove it from the manifold) and see if it still does it, this will tell you if it's the cat or not. Who told you it was an injector, and how did they come to that conclusion? It could be a fuel pump, you can use a fuel pressure guage to test that, or if you have the money replacing it at that mileage (assuming it's original) would be good preventive maintenance anyways. Amazon has them under $200 I believe, don't use airtex or other trash, delphi/delco only for this part. You'll need to stick the guage to the windshield to keep an eye on the psi while it's under boost.
Other possibilities:
Fuel pressure regulator
ICM
Coil pack (s)
ICM harness and/or ground
Bad EGR (not 100% on the symptoms of these going bad, I remove them immediately, just a thought)
Also, don't try and remove the plugs without having new wires on hand, unless you have a quality set on there now (taylor, zzp, msd, prj, etc) they're probably gonna be trash upon removal. Scan it for codes, some don't set the SES light, such as the one I had for my #1 injector going bad, p0201 iirc. That should be a good start, at least.
Other possibilities:
Fuel pressure regulator
ICM
Coil pack (s)
ICM harness and/or ground
Bad EGR (not 100% on the symptoms of these going bad, I remove them immediately, just a thought)
Also, don't try and remove the plugs without having new wires on hand, unless you have a quality set on there now (taylor, zzp, msd, prj, etc) they're probably gonna be trash upon removal. Scan it for codes, some don't set the SES light, such as the one I had for my #1 injector going bad, p0201 iirc. That should be a good start, at least.