Throttle position sensor

[Timl]

1051949

I am having a strange thing happen! When I am driving 65 the tach shows 2200 - if I lef off slightly (maybe a slight downgrade or even a good tail wind which we get here in North Dakota a lot!) my RPM's go UP to 2500! It is like the transmission comes out of lockup! I am wondering if anyone has experienced this and am suspicious of the throttle postion sensor being the culprit.

[addsig]

 

[MudderChuck]

1051986

Mine seems to want to lock up and unlock about 1500 RPM, with easy to moderate throttle. The more throttle I give the later it seems to lock up. Unlocking seems to be a bit more sporatic. I know it will unlock when I hit the brakes. Could be something about the compression braking function of your transmission, coast and the lock up not working at the same time (which logically they shouldn´t). If you suspect wrong shift points, the kick down cable is worth a look, as it also controls pump pressure, the adjustment is critical to transmission function and longevity. If you´r transmission is computer controled, disregard all of the above.

The temp. switch in the transmission also affects, lock up. You mentioned North Dakota.

Most aftermarket tach´s are a bit more sensitive, than the OEM tach. and will show many transmission functions you wouldn´t normally notice. My last add on tach. would show, lock up, un lock and partial lock, seemed to be tied to compression, more than throttle position (Chevy). If I hit a sweet spot (around 2400) the needle would swing around alot, as the torque converter did it´s thing.[addsig]

 

[Timl]

1051994

Well, it is a 90 Cherokee so is probably computer controlled? It has the factory tach and also does the lock/unlock at slower speeds but under extremely light throttle situations. The strange thing is that you really have to step on it tho get it to downshift at all on a hill or in a passing situation so the 2 seem to contradict each other![addsig]

 

[ddoffroad]

1052396

I had the same problem, just replace the TPS. They are like $50 and are real easy to do. You said you have a '90....thats what I have also, the TPS is located on teh front of the throttle body and is held on by 2 screws and the electrical plug. It may be messed up from water or dirt. You could pull out the old one and try to clena it before you get a new one, use some electrontic Endust! HAHAAHA... [addsig]