Bogging down at WOT in 2nd gear

[RedogOnyx]

For some reason, even with this problem I went 3 rounds on Sunday

At WOT, the car bogs down at high RPM's but only in 2nd gear.

1st time: @ 3850 rpms
2nd time: @ 4200 rpms
3rd time: @ 5100 rpms
4th time: @ 4500 rpms
5th time: @ 3700 rpms

The 5th time it never recovered, it was like I was hitting the brakes and then the gas. It got to 6000 rpms just fine in 1st gear, after the bog (I have to get off it and floor it again and it was fine thru the rest of the powerband) it shifted fine into 3rd gear at the correct shift point (around 5700 rpms. My 1/8 mile time was normal at 9.980 @ 71

What could it be? I read that there is another sensor on top of the TB that tells the TPS how open the throttle plate is, if this goes, the PCM goes crazy and bogs the car down thinking the throttle plate slammed shut.

Injectors?

fuel pressure?

Fuel filter was changed in March (at inspection I get it done, my inspection is in May, but I can get it done upto 90 days before the exp date)

Fuel pump is 2 years old

running a 1/4 tank of gas when this happened

[RedogOnyx]

anybody?

[3400-95-Modified]

Have any way of monitoring the fuel pressure during the run? Or the a/f ratio with a wideband? You may be loosing pressure or the injectors cant keep up and your leaning out like a bastard.

Your TPS will typically throw a code if its acting up.

[RedogOnyx]

I do have an a/f gauge, but its a narrowband light show but if it's leaning out that bad, it should show.

Hasn't done it since thou.

Hoping that's all it is, new injectors are an easy fix

[3400-95-Modified]

Don't go new unless they are actually fried... if they are supportive by flow numbers just send them to Witchhunter to get cleaned, they may just be boogered up.

[Superdave]

could be sensing knock and pulling timing.. weird that it's only in 2nd though.

[3400-95-Modified]

Unplugging the knock sensor would determine that...

Any way to datalog?

[SappySE107]

Unplugging the knock sensor will give you max retard all the time on OBD1. I doubt OBD2 likes that either.

[sprucegagt]

Unplugging the knock sensor will give you max retard all the time on OBD1. I doubt OBD2 likes that either.

There may be a few GP's this doesn't affect, but for most 60*V6 applications, you are right.

[3400-95-Modified]

Uh, My OBDII venture ECM did not give me max retard when I unplugged it... I was running my red car like that for a month till I was able to swap the engine because it was pinging like a bastard and registering knock and making it unbearable to drive

[sprucegagt]

Regardless, I still would not recommend it. There are way to many variables here than just KR. He has a late model N body and there is no reason why he shouldn't be datalogging this instead of taking a guess. Especially when it involves disabling a sensor that's designed to protect the engine under high load conditions.

[carbon]

What about the fact that it could be the tranny that's doing it and not the engine? I have read a lot about issues with the 4T45E having problems with max accel in 2nd gear... my friends Alero does. Revs fine through first, shifts to second starts to pull, then flys out, then starts to pull, then flys out, then starts to pull... etc...

If you left of the gas it shifts to 3rd and keeps going with no problems, if you manually select second gear it will not do it either...

[sprucegagt]

The early models of the 4T45E have pressure control solenoid problems. I believe they fixed this starting sometime within the '02 model. But the problem would make 2nd gear slip. Mine has been doing it for 3 years whenever the tranny temp gets above 130*F.