After reading several maintenance articles here over the weekend I decide that it was time to catch up on several things on my 01 4.6L 4R70W Tranny Supercrew that is nearing 100k, so I did the following.
1. Changed the oil (doesn’t it always start that way, like honey could you take out the trash? ). Despite the fact that the truck has 100k I have changed the oil previously.
2. Had a searching idle problem, decided to clean the IAC valve.
3. Read a little more and decided to clean the TB.
4. Changed the transmission fluid according to the instructions here.
5. Cleaned the MAF sensor.



Immediately after these changes the following issues showed up, NONE were present before with the exception of the searching idle.

So when I was done I started the engine and it would immediately die. I think that was caused by NOT replacing the EGR gasket which I did last night and now it does not die on starting. I also was still getting a searching idle so I REPLACED the IAC valve, that problems seems better but not entirely fixed the engine still is bouncing from 650 – 800 RPM at idle but that is far better than before. At highway speed I was having throttle response issues and got a P0122 error. I checked the TPS and it must have broken or gone bad when I put it back on the TB so I got a new one.

That leaves me with the following problem:

When I went out on the first test drive the transmission was slow to shift and it would not shift to 3rd until about 4k. I thought that problem might be related to one of the things I fixed last night (TPS, EGR Gasket, IAC) but I’m still having the same issue. When I changed the fluid I dropped the pan, cleaned it put it back, disconnected the return line and pushed through 13 qts of fluid and then topped it off so that all looks good.

So? What would have caused the transmission to start shifting poorly? Is there something in/on/around the TB or MAF that would cause that?

After two really late nights I'm just looking for somewhere to start (or preferably end)? Thanks in advance for any help.

 

how did you go about cleaning the MAF? Depending on how you did it, that could be part of the problem.

 

That was my thought as well. You spray it with electrical cleaner, let it air dry.

 

I followed the MAF sensor cleaning instructions located on the maintenance page. But specifically I removed the MAF sensor from the air filter housing. Removed the two screws that hold it in using a safty torx bit (T20) and cleaned it using electrial parts cleaner. I sprayed it with a bunch of cleaner but never touched the wires inside. If it's possible that the MAF might be linked to late shifting I was wondering if I got the connecter fully plugged back in? I thought about that last night but it was midnight and I was tired. If that is a possiblility I'll move it to the top of the list when I check things tonight. Can I test the MAF? and if so is there a thread on how how to do that?

Thanks.

 

The MAF could be tied to your idle issue. Should not have anything to do with your tranny shift problem.

I cleaned the MAF twice on my old truck and screwed it up the first time. It's a pretty sensitive thing in my experience. Not sure how about a test for it - you'll need to do a search.

 

I may clean it again to see if it clears up the idle issue, it's really not that bad now, just annoying. The main issue right now is the Tranny shifting late? I was thinking that it may be a vacumn problem? But I'm not sure what to look for first.

 

It sounds like you got into a number of problems and now see the total result that needs to be resolved one step at a time.
First thing is to be sure you have the TPS on correct so it operates by being linked to the throttle shaft. This is important because it is partly responsible to signal the PCM for transmission shifting. Suprise!
Next, reboot the PCM by removing the positive cable for 5 minutes.
Then restart the motor cold with the lights, heater motor and A/C on high and any other loads. This begins to retrain the PCM for full control. Let warm fully then go drive 5 miles and do several restarts to include battery charging in the relearn process.
It should smooth out from hunting and settle down to normal idle.
If not you have other issues to find.
Better workmanship is the key.
Good luck.

 

Bluegrass thanks for the note,

I've suspected the TPS all along as the main culpret. I will do what you've laid out when I get home. I did leave a couple things out in the interest of space. First, I disconnected the negative battery terminal for about 2 minutes last night and that seemed to help things but not solve them. So I will disconnect the positive terminal for 5 minutes tonight. In putting the TPS on I could not find a good "how to" guide so I just went with what looked right. The TPS is spring loaded so I installed it so that when the throttle is engaged it rotates the sensor (ccw) and loads up the spring and when it's released it goes back to the neutral (beginning) position. I'm assuming that's right since it seems to have no othe way to adjust it?

How "cold" does the engine need to be to retrain the PCM? Cold to the touch or just not "Hot"?