94 4.0 OHV Rough rich idle at startup

Hey guys, it's me again. Well JY engine has turned out pretty well. I guess I got lucky on that one. It's been running smooth and strong until about 2 weeks ago. Cold / hot, it doesn't seem to matter much but when I start it up it runs fine for about 1 - 1 1/2 minutes then it starts to run rough and give off that raw fuel smell. This will continue for about another minute or so and then it smooths out and runs fine from then on. My first thought was ECT sensor sending bad info to the PCM. I'm pretty sure it was the original sensor so I changed it out. No improvement. Checked the FPR for leaking through, all good. Fuel pressure at 35-40 psi before, during, & afterwards. So NOW what? It also started doing some strange things in the dash at about the same time. OK, maybe I didn't get a good ground somewhere when I put the new engine in... I went through and double checked all the grounds even ohming them out back to the battery & chassis ground. Nothing amiss there either. Just to be sure I ran a couple of temporary redundant grounds to check. No difference. It was then that I saw the link to www.auto-diagnostics.info describing the problems with 25 year old EEC IV PCMs going bad. I had never really given much thought to the PCM going bad from age but the symptoms sounded pretty familiar. So I need a little advice from anybody that has run into this before. I'm relatively sure that's the problem just not sure enough to plop out $200 for a reman one. I know that the capacitors can be replaced but I'm not sure that I'm still steady enough to operate on it myself. Besides, if I gotta replace any part of it i'd rather replace it all with one that has at least been looked at and tested by somebody who knows better than me.

Here's all the symptoms:

1) Rough idle for 1-2 minutes after startup (cold or warm),
2) The idiot light for the battery sometimes comes on, sometimes flickers (14.3 to 14.6 at the time. Checked with a known good Fluke digital VOM),
3) The park brake light (which hasn't worked since I bought the truck many moons ago) sometimes lights up when I first start up. But only sometimes.
4) The cruise control has also stopped working although I don't think it's related to this problem.

Any ideas / suggestions are deeply appreciated. I'll be the 1st to admit that what I know is far less than what I don't know. Thanks guys.

Really???

Really guys?.... 74 views and no one has an idea or suggestion? C'mon, help a guy out here. Everything I check and test appears to be working correctly or at least within range. I've beat my head against this thing so much I've about run out of brain cells. And I didn't have that many left to begin with. (haha)

I did pull codes again today and found a 512 (Keep Alive Memory Test failed) and a 565 (Canister Purge Circuit failure). Neither code set an MIL. The 565 has been a problem before but I thought I had it handled (replaced the charcoal in the canister, new CANP solenoid, new vacuum lines from canister to the intake).

Can someone please point me in a better direction?

Fuel Pressure Regulator(FPR) will be behind alternator down on the lower intake
It has a Fuel Return line, AND a smaller vacuum line, check that vacuum line for gasoline

If FPR starts to leak raw fuel is sucked into the engine causing flooded condition on start up, warm or cold

Thanks for the tip Ron. Unfortunately I had already checked that possibility and all was well with the FPR. I do, however, have another line of thinking that could very well turn out to be my gremlin. I'll get into it below but first let me say that all credit for that idea goes to you.

[Q] "Unhook battery!!!
Pull out the PCM
Remove the top, it should look like this: http://www.auto-diagnostics.info/ford_eec_iv

You see the 3 Blue capacitors, they will leak and cause problems after 20+ years or so
Cost under $5 to replace all 3, if they have leaked

How-to here: http://support.moates.net/capacitor-...-ford-a9l-ecm/

Yes, you can get a new/refurbished PCM as well.
Needs to match your model Ranger, manual or automatic trans is the big one, along with engine size.
Images here of PCM Labels: http://www.tweecer.com/images/CCHW.JPG

The circled numbers need to be matched as close as possible but doesn't have to be exact in most cases

ALL Ford PCM's use part number 12A650 in the center, same number in 2018
First 2 numbers/letters are the date in above example, E8SF-12A650-
E8 is the year, E = 198, 8 = 8 so 1988 year
F = 199 so F3 would be 1993 your model year

Ranger code is 7Z or 7F
So google: F37Z-12A650 and F37F-12A650
And you should get PCM listings for your year ranger, needs to be for a 4.0l engine and your type of trans
Last edited by RonD; 06-07-2018 at 02:11 PM." [Q]

Ron I found this reply of yours in another thread and when I read it my light bulb began to flicker a little.

My Ranger is 25ish years old and to the best of my knowledge the PCM is original. After doing a little research on the matter it appears to be a very common problem. I haven't pulled the PCM just yet, I'd like to have the capacitors on hand before I do. But I've got a couple of questions I'm hoping you can help me with to be certain I have the right parts.
1) Does the 94 Ranger use the A9L PCM for certain?
2) Do you by chance know for certain the specific values of the 3 capacitors? I have read that they are a 22uf@50v, a 47uf@50v, and a 100uf@16v. Are these correct?
3) While looking for the capacitors online I find a 47uf@50v AND a 4.7uf@50v. Without having the actual capacitor out of my PCM to look at which is the correct one?

I'm hoping to be able to pull the PCM, replace the capacitors (Lord I pray that IS the problem) and reinstall it the same day. I really can't afford for t to be down for long. Thanks for all your help and, providing this works, all credit belongs to you my friend.

Andy