1993 Ford Escort Rough Idle

[quote:a91f2b6d89="neodenium"]Hi, I have a 93 Ford Escort, 5-Speed 1.9L. It idles rough, with a steady drop in RPM followed by recovery. I've replaced all the general maintenance items (plugs, wires, filters, etc) and it didn't make a difference. Also, the check engine light does come on, but not all the time and it doesn't stay on either. Seems mostly to come on at high speeds, though not always. It also seems to accelerate slower than my previous escort (same year,model), though I could just be remembering incorrectly.

I just ran EEC diagnostics on it and it gave me a "Fuel system at rich adaptive limit at partial throttle/system lean (181)" code, a "Fault in injector pulse width circuit/high (186)" code, a "EGR sensor circuit voltage lower than expected (326)" code, and "Cannot control RPM during KOER low RPM check (411)" code. I'm thinking the last one is just saying that it can't control the idle, though maybe not? This being my second escort, I'm familiar with the MAF problems it can have and have read in previous posts that a bad MAF can throw a "lean" code, but I didn't get any codes for the MAF specifically. Any suggestions as to how to proceed would be greatly appreciated. Thanks![/quote:a91f2b6d89]

I think you are right on track with the MAF sensor. Personally I would attempt to clean the small little wires that do the sensing. You will need electrical cleaner that leaves no residue and is fast drying. Do not get too close to the wires when you spray them. Just a light coating should be enough to disolve and oil or dirt deposits that may have collected.
If this doesnt work, a new MAF sensor may be needed.

Ok, I'm going to try cleaning the sensor tomorrow. I was wondering if you think it would be wise/reasonable to see how the car runs if I unplug the sensor? I'm not sure if no signal is worse than a bad signal. I'm just hoping to be able to narrow it down to the MAF in case cleaning it doesn't work. Thanks again!

[quote:30589b348c="neodenium"]Ok, I'm going to try cleaning the sensor tomorrow. I was wondering if you think it would be wise/reasonable to see how the car runs if I unplug the sensor? I'm not sure if no signal is worse than a bad signal. I'm just hoping to be able to narrow it down to the MAF in case cleaning it doesn't work. Thanks again![/quote:30589b348c]

I do not believe the car will run with it unplugged. If it does, it will run in the closed loop mode and this will not be a good indication if the sensor is bad. Some times when the vehicle is run on a diagnostic machine, a bad sensor can be detected. It may be worth your wild to have the car tested, and see if it is indeed a bad sensor.