Reading Diagnostic Codes - '91 XLT; Need Help Deciphering!

[Thallarsen]

I've got some pretty serious missing/stumbling on acceleration; and some feedback is leading to fuel pressure regulator:
My earlier post about missing/stumbling
I'm now at the point of reading the stored codes (got an Actron reader from Autozone) Both the reader's instructions and my Haynes manual say that the codes could either be two digit or three digit numbers, but they don't say specific years. The Actron's instructions mention that the first set of codes are the KOEO codes "which are sent twice (so you can double check your code list)". Then there is a separator code followed by the Continuous Memory Codes, which are also sent twice. The Haynes has no mention of the codes being sent twice.
How can I find out how many digits my PCM is returning?
On the KOEO read, I'm getting the following:

Flash (1 sec. pause) Flash (1 sec. pause) Flash
(3 sec. pause)
Flash (1 sec. pause) Flash (1 sec. pause) Flash
(5 second pause) Flash (5 second pause)
Flash (1 sec. pause) Flash (1 sec. pause) Flash
(3 sec. pause)
Flash (1 sec. pause) Flash (1 sec. pause) Flash

Based on my little experience with this thing, I'm interpreting either 111 with a 'separator code' of 1; then 111, which would mean everything's fine.....assuming I'm on a 3 digit read.....BUT, if it's a two digit read, then it would be more like 33;with a 'separator code' of 1; then 33. That would mean EGR not opening or not seated.
Does a '91 have an EGR?
In the Haynes manual, it refers to 33 as a code for continuous memory & engine running; and not KOEO.
I'm kinda stumped here.

J.P.
'91 XLT

 

[Jason_25]

Pretty primitive huh? I got tired of dealing with the mess and I bought a scan tool for OBD I and now I don't have to decpiher the morse code

It will help you out to know that the 91 explorer does NOT have EGR. Also, it sounds to me like the computer is giving you the all clear.

Good luck with it.

 

[Runnin'OnEmpty]

JP, I also think the code is a 111/System pass.

My gut feeling is you have a bad TPS (throttle position sensor). These things are basically potentiometers, and they wear out in the mid voltage range. If you have a multimeter, they are easy to check. Your Haynes manual has the procedure.

When you test the signal wire, the voltage reading from idle to full throttle should be smooth. If it is the least bit erratic, the TPS is bad.

 

[Thallarsen]

Jason 25 & Runnin' On Empty

Thanks for your input. Every little bit helps. I'll be checking the TPS as the next step. It certainly can't hurt to check it.....If it's okay, it'll be just another component that gets an 'all clear' in the list of sensors, valves, lines, connections, wires, etc. that I need to check.
Eventually, I'll come up with the problem (probably something as basic as a bad plug, or something like that).
Thanks again.

J.P.