98 GTP cutting out at 4000 rpms????

[missouri girl]

I was driving along lastnight and my car started this weird thing at 4000 rpms. It cuts out and wont rev past 4 on the tach. No lights came on the dash nothing it just runs weird at high rpms....Please help because I have no clue and need to fix it....Thank you

[BNaylor]

Welcome to AF.

It would help to post your current mileage.

Was the cutout while moving - accelerating or only at idle? In Park or Neutral while idling the engine cutting off at around 4000 rpms is normal since there is a rev limiter.

Also, when was the last tune up? Spark plugs, ignition wires or fuel filter. Higher rpm cutout or misfire under driving conditions can be a secondary ignition issue or even a bad CAT converter.

[missouri girl]

It runs fine at an idle and low rpms. But when you get them up to about 4000 it stall and cuts out. It has 168000 miles on it and I am unsure about last tune up, I bought it used back in the summer last year and havent done anything to it. It has always kinda cut out going up hill when the boost was kicked in but that was the only time it would do that. I just have no idea.Thanks for all and any info.

[Mickey#1]

I'd start by replacing the spark plugs, air & gas filters. It sounds like you're due for an oil change also.

[grandprixgtx00]

spitting and spuddering under boost can also be caused by KR, are you running at least 93 Octane in your GTP? I would pull the plugs and see what they look like. May be time for a good tuneup.

[tblake]

93 octane may be hard to come by. 91 is about the best I can get in MN with the exception of a few stations that have 92.

I wonder if this could be an issue with the boost bypass valve, or a vacuum leak.