Another loss of power story

[tdaward]

First off, I've tried to get help on "that other forum" with little to no help....


1993 Ranger 4.0L 5 speed with 104K miles


The story goes like this: Intermittently the truck will loose power and the CEL will come on. If you cycle the key it picks up power again. The first trip to the computer it came up code 137, changed the O2 sensors, still the same. Had a code of 157 on next read. cleaned, got the same code, then replaced the MAF. SAME RESULTS ON THE ROAD. Replaced the coil pack, cleaned the ICM and TPS, ran the Chilton check on every sensor on the truck. Ran codes today and got a 137, 157 (MAF low voltage), and 538 (insufficient RPM cahange during KOER Daynamic Responce test) In the middle of all this I did have the muffle shop check the Cats and they seem to be fine. I'm at a loss and need my truck up to snuff!

What gets me is that it doesn't do it all the time or in a recognizable cycle ( up hill, down hill, load, unloaded, etc...) It just does it for different lengths of time also....some times cycling the key doesn't work some times it does.

Haven't found any vac leaks or loose wires.

also my code readers book says 137 is rich and my chilton says lean???????
From what I've gathered it is rich, and by the exhaust smell it's rich.....


Please throw something out there for me to bite on!

 

[Nhaz]

Only 100k on that truck I'm impressed. Hows the rust? Does the passenger side of the floor get wet or damp?

Pull the EEC-IV computer and check for corrosion inside its casing. Especially since that year like mine can pour water down the passenger side of the cab from outside and destroy that computer over time. Which can cause all kinds of fun problems.

If its corroded its probably done. If you replace it Put a heavy plastic bag over it and seal it before putting it back.

 

[tdaward]

I live in Texas, no rust....a LOT of hail damage, in fact it resembles a golf ball, but no rust.....It belonged to a Doctor friend of mine, I did some work for him (5 hours worth) and he gave me the truck. I was getting beat up on his farm by his kids and needed work. I gave it a loving home and it's been a good truck for two years.

I may have found the issue...The new MAF plug must not be exactly the same as the old...The plug would move out about 3/16" I zip tied it last night and it did fine. I'm gonna take it out on a long trip today and see.

It is always the little, hard to notice, things that get you!