1990 LX "Check Engine" blues

[FordEscortLX]

I have a 1990 Ford Escort LX. 1.9 L CFI. The car will idle and run fine until the “Check Engine” light comes on. When it does the idle bounces all over the place. At any given moment it will spike at 3K then drop to a stall. There are times when the light comes on right away (with the engine cold) and times when I’ve been running (normal operating temp), no specific pattern. It will go out, and the car run fine, just as suddenly as it comes on.

If the light comes on while I driving I have problems with acceleration and deceleration from a steady cruising speed. When I take my foot off the gas the engine stumbles hard and feels like it is going to stall. When I step on the gas it again wants to stall. The most sever condition is when I am cruising at steady speed, take my food off the gas, then step on the gas again (driving around the neighborhood for instance).

The stumble at acceleration is very similar to a bad accelerator pump in a carbureted system.

The car sat for several months, but I did not have this problem before.

I’ve replaced the fuel filter, PVC, checked the gas cap and vacuum lines. These seem to be common problems with other posters.

I’m looking for suggestions that I might try/check at home before bringing it in to be checked. For example, on early GMs you could jump a connecter and watch the light blink out a code. Is there something similar I can do? Are the symptoms I describe common to a specify part, such as an oxygen sensor? Any suggestions or direction to look, is appreciated.

JTF

[my69mach]

Had the same problem with mine.
Go to a junk yard with a security torx head bit from a local hardware store and take off the MAF (mass air flow sensor) located on the air filter box that is if you have one which I believe you do. It's amazing what trouble that one piece will cause.
I replaced nearly everything related and that was the only thing that fixed it.