The lack of error codes perplexes me. Usually this type of issue at least throws something at you, even if it's ambiguous. In my case I had a slew of codes, and the charcoal canister was one of many items I addressed.
Since you've done all the things per the book up to this point (which is the only way to go) I would start looking at oddball stuff. Sounds like it's something that happens only over time. Had an issue with a machine at the job where it would function fine while we were setting it up and dicking around in single piece mode, but when we turned the switch on and let it run the 5th part every time would be bad. Turned out it was a restricted cooling line. The mirror would cool down while we made adjustments, but one it auto cycle it overheated.
So is it a vacuum leak in the intake that only opens up fully warm, restricted cooling line to the TPS/Throttle body, electronics like the igniter flaking out once warm, etc. Sounds like a tough nut to crack in any event. Good luck.
I had a very very similar issue on our 90 fj62, it fawked with me on/off for over a year, replaced all the normal suspects.....I hated that damn 62, it just drove me nuts.
in the end.....one day when it was running like poop, I was leaning over in the engine bay with my hand on the black hose that goes from the valve thing on the fender(which goes to air pump) to the air rail(by check valve)......and it suddenly ran perfect! I looked and noticed the hose had a crack on it.....grabbed the self sealing tape, wrapped it up......been running perfect for 5 or so years. I have a feeling the crack opened once it warmed up or some such thing.
This is what I needed! Random stuff not in the FSM. I did blow out the canister lines, but have not replaced it. This I suspect is causing the pressures in the tank . The air pump tube is another great suggestion! Thanks for the reference pics. This sounds plausible but when we got the 62 and drove it the belt on the air pump belt has never been on it, it ran like a champ the first day. I have asked around and some people use it some dont. Seems to me like it should be on but maybe the PO took it off because the pump went bad. I have often thought it was a vacuum line opening when it heated up but it'll do it when its cold also. Cap and rotor are new. I'm looking into the ignitor also trying to catch the signal from that while it's being naughty...it's So intermittent it tough to record it... I will address these this weekend and get back to ya'll. I appreciate all the input. Anymore is definitely welcome. Thanks guys.
Update: After determining that the tank pressure just seemed to be to high when I would remove the cap I decided to order the Vc 120 vapor canister . Hooked the thing up and so far she seems to be happy. We shall see how she does in the next couple weeks. It's only been 6 months! But between school and Work I think in I've finally covered everything I needed to to get her back on the road. Now to work on getting a nice stance and some paint. Thank you all for the advice and pointers.
I'm glad it has helped! If I had to go back I would flush the canister valve with some brake cleaner and unclog it that way! But knowing I replaced all the stuff I did is a better feeling knowing it's mostly out of the equation when stuff is still wrong.
amen. mine was acting up and driving me nuts until I happened to grab the air intake hose and, all of a sudden, idle went to normal. hairline cracks on that big hose are very hard to detect. I duct taped all around until I got a replacement.
