1993 4.0 Ranger... running - but rough and rich. I cannot use an OBD scanner because it just reads 000, so i did the CEL "count the flashes" method. Without being too long:
KOEO - I'm getting multiple codes off each sensor... Voltage too low and voltage too high.... Coolant temp too low, coolant temp too high. This is true for TPS, MAF, Coolant sensor, and even gotten codes that in my book say "Cars only'"
KOER codes start with 998 (Failure mode) and goes from there with the multiple codes.
In addition, I checked the IAC and it was not opening. Tested voltage and red wire is 12v grounded to engine... White/blue wire is 11.8 when checked. IAC will not open though. Bench tested with 12 volts and ground and it works perfectly, plug it back in and no dice...
I've checked continuity from every sensor to PCM, all grounds, disconnected, cleaned and greased all connectors under the hood, checked for shorts, and still get nothing but a loping idle, rich running and an intermittent bleed down of fuel pressure once key is off. (new fuel pump, new injectors)....
I'm thinking it's time for a new computer module????

Any insight is greatly appreciated and thanks in advance.

 

Reads like computer issue

Pull it out and open it up, look at the circuit board for leaking capacitors, about a $3 fix, just did my 1994 computer

Computer is in engine bay drivers side, between firewall and inner fender, not to hard to take out, need a wobble to get the lower nut off the stud

 

Much appreciated. I'm going to crack it open and take a look. The inner fender liner is already out so removing computer should be a breeze. Hopefully, this will be my last post of questions and I'll start posting pics of it all going back together!

 

My 1994 had 2 bad capacitors, common failing after 25 years, I replaced all 3 of them

I bent over one that was completely gone, but upper right was also found to be leaking when it was removed
Caused all sorts of odd codes and engine issues
Not at all hard to change them but you do need desolder suction pump, wick didn't work well, and a fine tip soldering iron, lots of close parts you don't want to desolder, lol

You need two 16v 47uF, and one 63v 10uF

The diode in upper right was OK looks discolored but was fine

Both sides of the circuit board are sprayed with a sealer coat, that's what the "over spray" you can see is

 

After some tinkering and cursing... long story short... got a re manufactured Cardone ECM from O'reilly online. they just opened a new store in the little town closest to me. A couple of discounts and an online coupon brought the price down to $106.00.
I went ahead and swapped to a manual ECM so's to get rid of my 566 and 629 codes from the trans swap. Installed and started! NO CODES!!!! Tears of joy!!!!! It idles a little too low and has a little hesitation to it, but it's 1000% improved.... I can work with the idle , etc.
Now i can get down to the business of putting it back together and getting it on the road!
A million thanks to those who have chimed in.

 

Good work

Thanks for the update and the fix