Scottman27

Hello:

2.5 auto v6. here is the issue.
Start it up and put it in gear. drive it it will drive/shift fine. drive about a mile or 2 and the torque converter unlocks and let off the gas and the car will not go under 45mph. slow down and the car begins pushing you like your on the gas. slow almost to a stop and then you feel the trans downshifting and once it gets to a complete stop the throttle will come down and then start driving and in order to shift you have to let off the gas for it to shift and torque converter wont lock up and does the throttle thing again. so stop. shut it off and start and drive and then its fine for a bit then starts doing it again. sometimes ill drive my 15 miles to work without a hiccup and when i come home it starts doing it. I cleaned mass air flow and range sensor. replaced vehicle speed sensor and turbine sensor. and idle air control no luck at all.

I know this is electrical and not mechanical.

right now in order to drive it i have disconnected the idle air control valve and set the throttle body so it stays running, reset the computer. if i drive the car with normal to mid throttle pressure it shifts great you dont even feel it and does the lockup. anything over that and it feels like the trans does not know what to do or how to shift. Is it the PCM? any help is greatly appreciated.

thank you,

Scott

Bert

Take it to Autozone and they'll pull codes for free. With the IAC disconnected, does it idle okay and just not shift right? The throttle stop is very important to be set right. Did you count the turns so you could put it back where it was?

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Bert

Scottman27

I had taken it to a shop and they got no codes at all. the guy told me he let it sit overnight and drove it and put his scanner on it. and said definitely not a mechanical issue. because it comes and goes. he said its electrical. he recommended i replace vss and iac valve. so i replaced vss, and iac valve and it still does it, as well as cleaning range sensor, throttle body, mass air flow sensor. someone suggested the coolant temp sensor plays a big role in the iac and shifting as well as mass air flow and throttle position sensor?

what do you think?

its weird because sometimes it runs with no problem, then it just starts acting up out of no where, and i get no lights or anything on the dash.

Bert

It sounds more like a connection problem. I'd check all of the connectors and grounds.

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Bert

Scottman27

Thats what im hoping. there are so many wires on this thing i dont even know where to start.

Scottman27

Figure i would update you on what is going on. I took the car to my guy that did the trans job, he remembers the car and the job. he hooked his scanner up and we went for a road test. here the car pulled a throttle position sensor code. he cleared it and the car immediately settled down. we kept going for about another ten mins. and no codes came up which he thought was weird. So off I go to work afterwards and I picked up a new TPS. on the way to work it acted up once for a second at a light. so I got home later on and put the new TPS on. next day it acted up the whole way to work, no shifting, pushing, bucking. So last night I unplugged the battery and wedged a piece of plastic between the seat and brake pedal and left it sit all night so i make sure it clears any codes. Ran the car today and it had to relearn everything. so far so good. the real test will be when I try this out over the weekend when its 20 some degrees out. see if it acts up, thats when it usually does.

ill keep you posted.

Bert

Thanks for the update, do keep us posted.

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Bert

Scottman27

I will.

Scottman27

Well, here I am again. took the car out to get something to eat (35 degrees F out) (maybe 5 miles one way, started it up, went down the street, 1st shift fine 2nd fine. got on main road. no first to 2nd shift, had to let off gas, 2nd to 3rd let off gas, no torque lockup (no check engine light, no od light at all). got to food place. shut it off, ate came back out. went home 1st to 2nd fine, 2nd to 3rd, fine/ torque lockup was great flawless shifting. I do not get it. I am going to try to take it to trans shop again tomorrow. see if any codes come up. if none come up, i am replacing the computer. because what ever happens when I shut the car off, resets something on that computer to make it run and shift fine. cant be a short, or a bad connection if this thing gets sporadic like that (his scanner was saying the TPS was giving bad voltages before I replaced it). If I get no codes from this I am replacing the computer to see if thats the problem.