GT PT will not go over 2500 RPM

[jerrys]

I have a ’03 PT GT with just over 120,000 miles on it now. It has a Stage 1 Kit, BOV, catback Flowmaster dual exhaust system, VAK cold air intake and upper charge pipe system (from prototypepower) with a K&N filter, Screaming Demon Coil with Live wires and right now I have NGK 4306 (copper) plugs gaped at .060. It also has a few things that do not pertain to the problem I’m having. Most of the improvements have been on the PT for almost the whole time I’ve had the car. With that background the problem I’m having is that when going down the highway the car starts to “misfire.” That what I though at first. I mentioned this at one of our PT Cruiser Club events and my friend who also has a GT (with almost the same mods) said he had that problem (or so we thought) and the dealership said his coil was bad and replaced it. That fixed his problem. Knowing that I replace my coil with the stock one I had removed when I installed the screaming demon. This worked for awhile then started to do the same thing. I replaced the coil with my friends coil and again it worked for awhile. Both times approximately 30-45 days. I began to read on the forum about other things it could be. This past week I ordered a new coil (SD) and new plug wires (LW) and put a new set of plugs, the NGK 4306s. I was a happy camper…things were going along quite well (two weeks) until this morning. You guessed it…the same problem. So as I was driving down the freeway losing speed/power I started to look for other symptoms. This is what I observed. The engine was at normal operation temperature. The ignition system seemed to completely cut off; it seemed as if there was no spark to any of the plugs. When this problem is happening the cruise control will not work, it worked before as I was using it, and as long as you are going below the speed of 65mph and engine RPMs are below 2500 you can go along your merry way. But as soon as you exceed 2500 RPM the problem starts. Also from a dead stop you can accelerate normal up to 2500 RPM then the problem starts. The check engine light is not on during the problem. Once the engine is turned off everything goes back to working perfectly…for several days or just a couple of minutes. Sorry this was so long…but wanted to give as much information as possible. Any help would be greatly appreciated.

[slartyblarfast]

ok.... Don't quote me on this but I believe there is a TSB for this problem.... I think it involves replacing the PCM but I'm not sure. Let me look tomoroow at work and see what I can find.

[CREWZIN]

Thanks for checking on that Slartyblarfast. I was going to suggest hooking an OBDII scanner up and seeing if it shows up anything.

I did some searching and found someone that also had a problem above 2500 and it turned out to be the transmission. Here's what was said...................

I knew it was going to happen someday.
Everyone seems to agree that Chrysler auto transmissions suck.
I punched it after leaving a toll booth this weekend. About 85% throttle.
Tranny slipped, got off it and then continued. Seemed okay. A few miles later a MIL.
Car goes into failsafe mode when trying to shift above 2nd gear.
There were/are no noises from the tranny.
Topped off the fluid, disconnected the battery, its fine for a few blocks (till I go over 2500rpm) then its back to failsafe mode.

Went to Lee Miles for a free diagnostic.
Scanner showed - P0733 Gear 3 Incorrect ratio
Lee Miles tech says its a mechanical issue in the unit.
He wants $400 to drop the tranny and find out, around $1500 when its done.

[bobs turbo pt]

my first gt did this the dealership had the car for 47 days couldn't fiqure out the problem so they gave me a new car !!

[Taggert_LOA]

well first off your plug gap is way too big. stock gap is 0.40. you could be getting spark blowout. you might want to back it down to 0.35 and give that a try.

[nevinsrt]

Originally Posted by Taggert_LOA

well first off your plug gap is way too big. stock gap is 0.40. you could be getting spark blowout. you might want to back it down to 0.35 and give that a try.

X-2 thats way too big.

[quicksilverdon]

Originally Posted by Taggert_LOA

well first off your plug gap is way too big. stock gap is 0.40. you could be getting spark blowout. you might want to back it down to 0.35 and give that a try.

Agree. And easy enough to try.