I've noticed a new trend in my car's RPMs since I installed the BBTB and BIM last month. If I'm cruising along at highway speed, and I punch the accelerator to the point that the car picks up, but doesn't downshift (this is an A/T), the RPMs will pick up to about 4K, and as the car accelerates, the RPMs will drop to about 3400 and then pick back up. The car is accelerating smoothly during the whole time, and this whole drop-and-return process only takes about two or three seconds before the RPMs are back to where they initially started, and will continue to climb from that point on.

God, I don't think I did a good job of explaining this. Let me give a short timeline.

Crusing at highway speed...60-80mph
Step on accelerator, maybe 1/2 to 3/4 throttle
RPMs rise from cruise idle (3K) to somewhere between 4K and 4300.
Car accelerates, but RPMs drop to 3500 over the span of 1 to 1.5 seconds.
RPMs come back up, car continues to accelerate.
RPMs return to 4K after another 1 to 1.5 seconds, and continue to rise smoothly so long as I am accelerating.

Any ideas what might be causing this? I know already that I need to do another check of where I have my throttle cables adjusted to...the accelerator doesn't mash to the floor anymore like it used to, which makes me think the cable is a little too tight. At idle, the throttle DOES close completely. This was the main criterion I was trying to meet when setting the cables after TB / IM installation.

Any ideas?

 

i think its your torque converter locking up again. while you're cruising it will be locked but it will unlock for you to accellerate, then the car see that you aren' trying to accellerate faster so the converter will lock up again and you will continue to accellerate at the same pace.

 

Why did it never do this before, then?