Intermittant limpmode

[Azplinker]

bad caps in ecu, like all do 1 time, 89-95
if you drive with that jumper planted, DLC conn. and the 12 cadence stops or skips mid-stride that is, CAPs bad (ecu crashing)
it must do 12s full time running, this is not hard to do and is first on the list, as is EGR sticking open.

there are lots of fail modes for stalling, over 50 most are inside engine, so if it runs ok , mostly, then it's not low compression. and is EFI related.
one other fail mode, is exhuast leaks. (#4 exhuast man tube cracked wide open sucking in air, causing 02 sensor lean and engine very very rich. misfiring, and wanting to flood out.
but the 12s is first.

the other reasons, front crank bolt loose and cam jump timing? some even jump back. most just go retarded cam and stay here. but not always.
bouncing cam belts are like drunk monkey.(unpredictable)
day one,? check it? that bolt at 94ft/lbs, 17mm head.

pull the PCM yet, and look for green death, (day 2 check)
see the hell page.

ok, the o2 out , was rich, very rich. implies it may be ok. the 02. but should not go way rich, (SEEMS exhaust is not cracked)

the FPR likes to jam this old and can jam either way, open or closed, (closed floods engine, but stuck open causes weak power dueo to low fuel pressure)
pull the PFR hose off, is the vacuum line leaking fuel, bingo.





http://www.fixkick.com/ECU/hell/html/index.html

ever do a full tune up,? with filters. air and fuel. all spark parts, and wire sets?

this ecu does not store DTC for long, like new cars.
and they can clear fast. hiding the cause, so drive with the jumper let it flash 12s. (or it goes dead, or?)
500 rpm mostly is EGR stuck open. i clean it and defeat it the prove is not cause, then put it back after i fix true cause.
500 can be flooding (spark tips soaked in fuel)
500 can be lost fuel pressure.
or stuck closed ISC, if the idle can be returned to 800 -1000 easy with your right foot, this is a sign that the isc may be stuck closed.

id be sure the crank bolt is tight, and 12 work running, first.

---

Changed bad caps last year per your recommendations. Pulled FPR hose and felt vacuum and idle speed raised to 2k. No fuel leaking. Have changed filters, fluids, wires and dizzy cap last year. Last issue was blowing out coolant so replaced 195* thermostat with 185* O'reilly one.