Have been having a problem recently. It is a 2003 GT and at WOT in second and third you can see the rpm sit and then spike up. I was thinking maybe a fuel is cutting out but im not sure. checked the filters air and fuel no problems all plugs are fine no carbon deposits from lack of fuel. So i have no ideas as to what is going on thanks in advance

 

Automatic or 5-speed?

 

Not trying to hijack.....

But cliffy why did you ask about the tranny? Mine is an auto....continue reading.

I have noticed that after my canned SCT tune that once I go WOT the RPMs hang up for like a second and then rush forward and send me flying like hell. My perception has always been that its simply the time it takes for the computer to recognize the WOT position and make the appropriate changes based on the tune.....changes that arent part of the stock tune? Am I making sense here?

Mine definitely runs like a champ no problems but I can really really feel a difference when I go from 90% throttle to WOT after the RPM's "hang up."

 

I asked because it is quite possible that the PCM would hold the engine RPM at some perceived "optimal" RPM while the torque converter was doing it's thing--then lock-up and let the engine take over.

Once you start modding a modern auto transmission vehicle--I.e. modifying the torque curve to be different from OEM--the need to also tweak the electronically controlled transmission becomes more imperative. The engine's output and the transmission control are joined at the hip.

I wish I could help more, however the last "slushbox" performance car I owned was a '69 Charger Daytona--long before there was electronic control of anything...

 

It is an automatic. But the tranny is chipped just like the car. I have no performance part in it its completely stock.

 

When the RPMs are "just sitting there..." are you still accelerating? If so then there's something going on in the transmission control program or the transmission itself may have a problem.

Maybe someone who understands modern automatic transmissions can help--I know nothing of them...

 

If you could explain just a little more in detail the problem, Im thinking it may be similar to an issue I had with my auto in my ranger with the blower. Has this been happening for a while? Or did it just start out of nowhere? We need lots of details please.

 

Well i just bought my car so i dont know its been happening since i bought it. What happens is when i punch it she screams up the RPM and then sits it doesnt accelerate anymore I can actually feel it bog which is why i think there is a fuel cut. But then it catches itself goes fine. Shifts hard into third and does it again at around 5 or 6 grand. Also when cold started it seems to bog. If i rev it she will sometimes smoke because it gets to much gas.

 

Any help please

 

It sounds like who ever tuned the car didnt adjust the shift points where they're suppose to be. I kinda have the same problem with my car at the moment and trying to tune it and figure it out myself. As I punch it and it gets up to 40 MPH the RPMS sit there and then go again.