My 98GTP with a reprogrammed ecu from 3800performance.com will tend to stay in 1st gear for what feels for an extended period of time under full throttle. If I just let off the throttle of a moment it will go into 2nd but if I stay full on it will stay in 1st into the redline. Is there a reason this tranny will do this?
trans sitting in 1st under full throttle
- Thread starter reem98
- Start date
BillBoost37
New member
Has this always happened since you've had the pcm?
Hippo Machine
Because Wet Leaves
Are you in park?
BillBoost37
New member
Transgo... but a shift kit isn't going to change the rpm at when it shifts. That's totally electronically controlled via the programming.
NegativeOne13
New member
Do you know if there has been any valve train upgrades performed?
Trannyman95
Transmission Expert
The 3800 Performance tunes used to be / may still be DHP tunes. The 1-2 shift is set in the 5600-5800 rpm range BUT with an aging or tired trans the 1-2 shift will have a lot of lag from commanded to actual shift rpm, often around 300-400 rpm after it was commanded to shift which is often enough to bump the rev limiter on a 1-2 shift. A shift kit may help out but isnt the route cause of the problem. An out of the box Transgo kit is not going to give enough difference to notice much on the 1-2 shift so it will need to be modified to make a more aggressive change if you decide to try this.
So I changed the trans filter and fluid with mobile 1 synthetic and it seems the slow 1-2 shift is still there. but as I observed the car more closely it seems like it is shifting at the correct point 5600-5800 rpm with the 3800 performance pcm upgrade. but I think it's more that the motor is hesitating after 4500 rpm up to 5600...almost like it's running our of air or something but the boost gauge is at full. Could my TPS or maf be causing slow acceleration at high rpm. The car pulls great when it shift's to 2nd
How do I check the tps?
How do I check the tps?