2.3L ('83-'97) 97 Ranger 2.3 will not idle

[Mr.Pickle95]

Hello all, I'm new to this site. Just got a 4 cyl 5 speed ranger with around 230,000 miles on it, good shape but it has a major driveability issue. It will fire right up, to 1500 rpms and then immediately die. It refuses to idle on it's own and if you tap the gas you can keep it running, but it misfires and back fires until im giving it half throttle. Will run fine if I floor it. As I'm driving it feels like the ignition is cut off until I give it about half throttle and the ignition comes on, there is no engine response until I push the pedal far enough. There were a few instances where this problem suddenly went away and it drove and idled fine, but never lasted long and would revert to running horrible until I really pushed the pedal. I cleaned my MAF sensor as it threw a code showing low input, I also replaced the throttle position sensor, after doing this I made sure to drain the capacitors in the PCM so it would relearn. Still wont idle and I'm not sure what to look for next. Maybe bad ignition coils? Any input is greatly appreciated!

 

[sheep herder]

Idle could be the IAC valve. (idle air control) You can take it off and try cleaning it.

 

[Mr.Pickle95]

Forgot to mention that I cleaned the IAC too. Not sure if it's working right but it is clean.

 

[scotts90ranger]

mass airflow systems get really mad when they have an unmetered air leak (AKA vacuum leak), that's a big reason why I like speed density fuel systems more but apparently the emissions are better with MAF... That's my best guess for now if there's no other codes, unless the MAF is bad or there's some bad power/ground's involved in the MAF...

 

[Mr.Pickle95]

I verified the MAF has 12 volts on the 2 ground wires and power wire. Haven't found a vacuum leak yet and the fuel diaphragm appears to be good because its line isn't wet with fuel. The MAF might be sending erratic signals

 

[Mr.Pickle95]

Also, last night I replaced the ignition coils because my timing light showed erratic spark consistent with the engine misfiring. It did this on several plug wires so I thought coils were bad. Fired it up and ran rough as usual for a minute then cleared up and ran flawlessly on a 15 minute drive. Shut it off and restarted to see if I fixed it and it was back to running bad again. It always runs a lot worse if I just turn it off and start it back up.