DieselDaze

Hey guys, I'll do the best I can to explain the symptoms in a hope you guys may be able to direct me trouble shooting this issue.

The issue is a "flat-spot" around 1700-1800 rpms under acceleration.
Example: I am accelerating from a signal on to a freeway on ramp. Truck accelerates normally until it hits about 1700 rpm. At this point, the trucks rpms seems to level off - as if I eased up on the throttle.
To get through this, I actually have to press harder on the accelerator until the truck reaches about 1800 rpm, where it then resumes normal acceleration.

I can only explain this as a flat-spot in the acceleration curve.... it feels almost like I hit a really heavy head wind between 1700-1800 rpms.

Temperature also seems to change the dynamics of this issue.
Cold outside temperature - relative cool engine temps, and this flat spot is more pronounced.
That is, it comes on harder - almost as a miss, then clears up quicker.
Warmer outside temperature - relative warm engine temps, and this flat spot is more passive. That is, it seems to come on more gradually, lasts a little longer, and dissipates more gradually.

Once on the free way, torque converter locked up, the issue does not seem to occur... or at least, I can not feel it anymore.

Any ideas?

infidel

I'm thinking slipping tranny.

DieselDaze

Yeah, I thought of that too.
However, I figured if the trans were slipping, wouldn't the RPMs increase and speed decrease as the trans slipped?

In this case, both the rpms and the trucks momentum level off as this issue occurs - even as I increase throttle pressure.

joem

mine does that too, but at 2200 RPM and I always thought the pump was de-fueling right at 2,200. Mine throws me back in the seat when I floor it from a stop then throws me forward just has hard right around 2,2000rpm and well before it grabs 2nd gear at around 2500rpm, once in 2nd it fuels hard and throws me right back until it defuels again and throws me forward before it catches 3rd. Its so annoying I plan to do a 4k GSK just for this very reason- I also notice zero smoke as it levels off the a huge puff of black and breaks the tires loose when it catches the next gear

Ronco95

A 3K GSK will fix that too, without the need for valve springs.

My truck has the same "flat spot" at partial throttle. Accelaration falls off slightly as the tach climbs thru the same range and then simply picks back up until the next shift or I release pressure on the throttle.