I have a 1990 manual transmission fuel injected Mazda B2200 with about 202k miles on it. At first it seems to just stall at idle. It can either be a cold start or stopping at a light after driving it for a while. I can start it right back up but it will only run for a few seconds and then it will stall again right away unless I keep on pressing and releasing the accelerator peddle quickly. It doesn't seems to help if I simply hold down the accelerator peddle. I tried to get it in gear and it ran rough and I had to keep playing with the accelerator to get the car going. Once it got up to speed it seemed to run somewhat ok and I was able to limp back home that way.

When I got home I did searches online and removed the idle speed control unit along with the throttle body. BAC valve and the solenoid valve (ISC) both tested ok according to the service manual (BAC air valve was testing by soaking in near boiling water to verify valve does close; solenoid valve was tested via ohmmeter). I went ahead and cleaned both the idle control unit and the throttle body and reassembled everything back. The car ran great for a few days and then the problem reappeared. At first just rarely but now seems to be most of the time.

I've bypassed the fuel filter on high pressure side to no effect. The fuel pump is pumping out fuel but I don't have a fuel pressure meter to verify the pressure yet. Spark plugs and plug wires are only a few months old. I didn't notice any condensation issue in distributor cap.

Can someone please give me some tips and the rational behind it so I can try to fix this myself without just randomly replacing parts. I can't really afford to take it to a mechanic now because they just replaced the ECU on it a few months ago so they already have all my spare money x.X