So I seem to have 2 ongoing things with my 90 240, but thats typical. I have 203,000 miles now, and i have been trying to pass smog in CA for a few months. It was very close to passing but because it was idling a bit high, like 11-1200 rpms, so it wasn't passing.
to work on the smog problem in the beggining,i replaced the cat, header pipe, and anohter piece to fix the exhaust leaks. I cleaned all the intake parts, iac, amm, replaced all the vacuumm hoses, replaced intake pipes where needed, and tryed to make sure there were no leaks. My TB clicks twice when opening and closes the flap, but my idle screw is all the way out. I got injectors from the junkyard and had them refurbished so they are like new.
I also took the egr out, disconnected the two pipes so i could clean them out as well. I also checked to make sure the piston thing inside moved in/out like its supposed and seemed to move freely.
I changed the timing belt, tensioner and all front seals, and set all the timing marks. I am not an expert mechanic, but the cam is straight up over the first cylinder like i have read it to be, and it ran way better than before so it seems correct. i will check this weekend to make sure since its been aboue 2 months since i did that.

To get to the point I have a idle around 1200 and it isnt helping me in trying to pass smog. The car starts up without hesistation and goes to about 900 rpm, then first time you push the gas it revs up then stays arouns 1200rpm. If I drive for 50 miles or more and then get off the highway and come to a stop, the idle will sometimes go to normal and drive fine, until the car gets turned off again.
Also anytime i disconnect the negative battery cable to work on my car, when i am done and reconnect it, turn on my car, it starts and idles for a few seconds but then dies. have to give it gas to keep it going. It runs erratic, but then I drive for a little to get its idle back, then idles high.

I unplugged to hose from iac to intake hose, and the car dies, so i dont think the iac is bad. When i unplug the vacuum hose on the fpr it idles higher, so that shoud be ok. I am going to take the intake manifold off this weekend so i can change the gasket, jsut to make sure thats not the cause. But while i was at i think i should clean or replace the pcv stuff just to be sure cuz i haven't yet, but i have cleaned the flame trap.

For the egr, i pulled the lower hose vaccuum hose off the booster and i didnt feel any vacum suction. I did pull the top one off and that had good suction, so i dont know if the bottom one is bad or something. I pointed a flashlight at the egr to check for movement of the piston thing when i revved the engine, but i didnt look like anything was moving in there.

I am just running out of ideas cuz i feel like i've checked everything i know and everyhting i have read from forum searches, and the faq's page.
I did purchase a used, but good ecu almost a year ago because i had a 500 series and it crapped out on the freeway, so i replaced it with the correct 900 series ecu. So if it is something with the ecu i dont know how to check it.

Sorry for the really long post, it is hard to explain everything by typing it out. Any advice is greatly appreciated!

Andrew
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1990 240DL 201K+ 25/25 IPD sways