sounds to me like its starting in 2nd gear. possibly tps? or throttle cable tension?
when my bmws tps went out it was really slow, starting in 2nd, and wouldn't shift until high rpm also not even go into 5th gear (5speed auto trans)

im no expert on jeeps, but mby a place to start is check those

 

It starting in second does make sense, is there a way to test/check the tps and the throttle cable tension?

And thanks for the fast reply.

 

well throttle cable tension should be tight, somewhere on here someone posted about a "quick easy great fix" that smoothed out shifting response and downshifting on hills and it was just pull back the throttle cable a few clicks. something I had already done and is common with most auto trans. as far as the tps im sure thier is a certain voltage and ohms it should read but im not aware of what it is, a search might provide the info. and im sure at some point a more jeep oriented guru will come on here and fill in the blanks.

Like I said Im used to bmws and jap imports, american cars are a new breed to me, although they still share the same principles of most late 80's and 90's cars.

 

Okay, I was told it could be the 1-2 shift solenoid...does this sound plausible?

 

Do the TPS adjustment, first. Could also be sticking solenoid. You'll have to search for the write-ups these.

 

x2 tps
but yours is not adjustable. only the renix ones are. you need a replacement.
also check the inline fuse in the harness that plugs into your TCU just to rule that out.

 

mine did the same thing and it ended up being one of the shift solenoids in the tranny. when it got warmed up if would fail but cold nothing wrong with it. flushed the tranny before i put the new ones in and havent had a problem since.

 

What is theTCU?

 

transmission control unit.
it's under the dash knee panel on passenger side. there is a large wire harness going into an aluminum box approx 4x6 inches. that harness has an inline fuse. can't remember if it was 10a or 20a.

 

Lots of you tube vids on adjusting the throttle cable and kickdown cable. I would make sure its not something simple like this first.

 

TCU location

 

Also could be poor connection at the plugs. Here:

http://cruiser54.com/?p=58

 

I just asked this question a couple days ago on the forum, I had the EXACT same problem and I resolved it in 30 seconds. All I had to do was adjust my throttle valve cable/kickdown cable. Just follow this youtube video. It fixed my problem 100% in seconds

 

I can surely say it is NOT the TPS. The TPS will not know the difference between D and 1-2 on the shifter therefor you'd still have the same issue.

Thanks for posting that Henry, I was just about to post your thread and recent fix to the same problem!