Finally after my 99 2wd sat for 2 months, I drove it today to find the tranny wasn't behaving itself. It up shifts crisp and smooth and same thing with down shifting. The problem I am running into is when I hit 30 mph it shifts out of 3rd and stays in 2nd like with the tow haul mode. I checked by pushing the tow/haul button and the shifts are different so this should be the problem.

It does this till I either reach 35ish or 2500ish RPM's when it shifts back into third. The fluids look good. I'm hoping the computer just needs to relearn possibly not that I have a transmission purchase coming up soon.

Any input is greatly appreciated!!

 

That does sound like and odd sensor or tuning issue to me I would definalty look there first , I really cant think of a trans issue that would cause that.

 

It is the stock tuning that comes from the factory, just that it sat for 2 months

 

There may be a bad sensors somewhere, I would rive it a few days as long as the shift feels good , Is the speedo working correctly ?

 

Yes it is. Seems to be accurate with GPS testing it

 

Unless your TPS is more than 60% when this occurs, this shouldn't happen. With that said, I'd be curious about the reported throttle position more than the VSS (since you say the speedo is working).

 

I am going to replace the TPS sometime this week hoping it fixes the problem.. I disconnected the battery for 10 mins and it made no difference. I don't have access to a data logger either which kinda sucks and I could find how to check if the TPS is working smoothly

 

Well, if you have a voltmeter, check the voltage from the 'Signal Return' wire. Of course, find a good ground for your negative (black) probe. At WOT, that voltage should be above 4VDC (Note the ref voltage is only 5VDC). At 0% (closed position), the voltage should be under 1VDC. Depending on your voltmeter, you may or may not be able to probe the backside of the connector to make contact with the pins. I've seen instrument techs improvise in similar situations.

I'm no ASE-certified mechanic, but I would start there if I were suspicious of the TPS being at fault. (see attachment)

 

Thanks..I will give that a try tonight