Tranny randomly up and downshifting

[SeanMc]

It happened again, but only after having to hit the brakes hard. Also, when sitting at a light, it almost died. When cruising you can feel the revs go down and then up again, and sometimes up to the point where it needs to shift. Speed never changes though. Would an IAC cause an issue like this?

 

[hawkeye18]

not if you aren't idling. Are you sure you aren't having TC issues?

 

[SeanMc]

not if you aren't idling. Are you sure you aren't having TC issues?

I think you may be on to something. When cool, everything is just fine, but when warm (or after about 15 minutes of driving at freeway speeds), stuff starts acting funny.

 

[SHO_DOODmorrris]

did you pull codes after it did it again?

 

[SeanMc]

did you pull codes after it did it again?

Yeah, 111.

 

[SeanMc]

I found a plug wire loose...again. Put it back on, and drove the car hard for 30 minutes, couldn't reproduce the problem.

 

[TYSHO]

Sounds like a race car!!!

 

[SeanMc]

sounds like a race car!!!

ugh...

 

[SHO#7]

Check your range sensor. Better yet, for 40 bucks, replace it.

I have seen many a ford that get false info from it. The car basicly thinks you pulled it down into 2nd, or first. Making it shift into an erratic gear for no reason at all. It thinks you are doing it...

Espically since you had connections growing hair. May be inside the sensor as well.

Mike

 

[SeanMc]

Check your range sensor. Better yet, for 40 bucks, replace it.

I have seen many a ford that get false info from it. The car basicly thinks you pulled it down into 2nd, or first. Making it shift into an erratic gear for no reason at all. It thinks you are doing it...

Espically since you had connections growing hair. May be inside the sensor as well.

Mike

Uh, where is that located?

BTW, thanks . You, Mr Anon, and Jason have been a big help.

 

[St Louis SHO]

The neutral saftey switch. Follow the shifter cable, its under it on top of the trans :wave: Although, I agree with Mr A, it sounds like a failing VSS.

- James

 

[hawkeye18]

OMG yes. I didn't even think of that. I was having HUGE issues with my TRS (Transmission Range Sensor), or NSS (Neutral Safety Switch), or MLPS (Manual Lever Positioning Sensor) - a doohickey of many names. It wouldn't recognize that I had shifted it into park, so shifting into drive elicited a huge WHUNK as it shifted into D. It was not cool. Also, I couldn't read codes at all! The EEC will NOT generate codes or go into KOER unless the TRS is telling it that it's in park. It also wasn't aligned right, so my reverse lights were all funky... anyway, definitely change that. You also need to align it right..

Easiest way to align it if you don't have the tool and you aren't by yourself is to wait until night (make sure you have a flashlight!) and back the car up to a wall. You will need a 13mm deepwell socket and a 12" extension (at least). It will also be very handy to remove the air box and hose to the TB. Put the key in ON (don't start it) and put the parking brake on. Now shift into R. Jigger it until the reverse lights turn on. Now get back into the car and shift into and out of R in both directions. The lights should turn off... well, when they should turn off. Same for turning back on. This is why you backed your car up to a wall at night... so you can see if your reverse lights are coming on. If they aren't coming on at the right time, adjust the sensor again... keep doing it until it works just right.

 

[SeanMc]

So I give the cruise control test another whirl, and it takes 3 time of me holding down the button to get it to go, and while accelerating, it would turn on and then off. Then, the CEL came on. Turned off cruise, and 2 minutes later, the CEL went away, and no code. Shifting then started to only shift at 2500rpm, then after stopping, 3500rpm. Then CEL flashed, and all was fine again. I'm going to take a guess and say it's my VSS.

 

[pccorrig1]

Mine did this when I first bought it over 10 years ago. It was a defective VSS, and I believe the code was 542. I had to drive into the dealer while the problem was occurring for them to read the code, which clears during those times when the car is running correctly. No problems since, over 10 years and 110,000 mi later.

 

[SeanMc]

It was a year and a half ago that I had it changed.

 

[SeanMc]

Ok, this only seems to happen when the air conditioner is on. Haven't run it in a month, and everything has been perfect. It's warmed up a bit, I'm running the air, and it's starting to happen again.

 

[SeanMc]

Trans oil temp sensor. Code 637. Oh fun. I'll get the VSS, TRS, and MLPS swapped out while they are in there.