Startup Issues

[jessep28]

Okay, for the past few months I would peridoicly experience a noticable abnormal vibration that would just go away a few seconds after startup. No SES light and was told that it was probably a temporarily stuck injector and not to worry about it.

Tongiht, 15 miles away (can't be in the driveway) from my house, the same thing happened. Only vibration got worse after placing it in gear followed by SES light. I tried shutting car off, starting it again and same issue happened.

I moved it about 200" to a wide open parking lot so I don't get towed since it was late at night.

Here is my list of culprets:

1) Clogged Injector
2) Fuel Pressure Reg.

Engine sounds fine from the exterior (no strange noises) but you can feel the vibration inside. Car idled at 1000k.

Hopefully I can get a code reader out there tomorrow. Any other troubleshooting ideas? Thanks for your help.

[jessep28]

You probably want my model info (stupid me)

2000 GT 3800
45000 miles (roughly)
no modifications

[BNaylor]

With the low mleage you have it may not be a clogged injector or fuel pessure regulator. Get it scanned and post back the DTC error code.

If you're intent on the 2 possibilities mentioned run some good fuel injection cleaner through the system.

On fuel pressure, check the fuel pressure at the Schrader valve (45 - 55 psi). For visual inspection pull off the vacuum line on fuel pressure regulator and look for fuel contamination or possible diaphram leak. Clean the throttle body and specifically passages where the IAC is located. Clean the MAF sensor with electronics cleaner.




Thrasher CAI, DHP v1.0 PCM,
3.25 SC pulley, CAIT GMAF, Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 TB,
TB spacer, MSD 8.5mm wires, Autolite 104s,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials

[jessep28]

I had it scanned and there was just one code: Cyl 3 Misifre...I forgot the exact code number since I didn't have anything to write down with me but I am 100% positive it was the one aforementioned code.

I was driving it up to a garage and the rough idle subsided. Not to say that there isn't anything wrong, but I felt better taking it to someone I trust

[BNaylor]

Originally Posted by jessep28

I had it scanned and there was just one code: Cyl 3 Misifre...I forgot the exact code number since I didn't have anything to write down with me but I am 100% positive it was the one aforementioned code.

I was driving it up to a garage and the rough idle subsided. Not to say that there isn't anything wrong, but I felt better taking it to someone I trust

The garage or shop should have the proper diagnostics equipment. They should be able to run a fuel injector balance test. Sounds like your problem is centered around #3 fuel injector, spark plug, the wire or ignition coil.

Its a good idea to get it fixed as soon as possible because misfires affect your driveability and could lead to possible CAT convertor damage. Good luck and let us know how it turns out.




Thrasher CAI, DHP v1.0 PCM,
3.25 SC pulley, CAIT GMAF, Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 TB,
TB spacer, MSD 8.5mm wires, Autolite 104s,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials

[jessep28]

Had diagnostic run and it turned out to be an arc in the spark plug boot. This arc was casusing the radom misfire.

Replaced all plugs and wires.

I had them do a fuel system cleanup since there was a ton of carbon buildup.

On just the carbon buildup: I was told by our mechanic friend, KC that I need to run the car agressive time to time to keep carbon from building up in the fuel system. Is this true?

I bought the car with 38k so there is no telling what damage was done beforehand.

[y2kpa2]

It Never hurts to "Blow It Out" on the interstate, that does help to clean Some of the crap that builds up in the engine just watch for cops!! you dont need a speeding ticket, i agree with bnaylor3400 you should also use a good injector cleaner that will help keep your fuel system clean. good luck!!