Still acting up

[parris001]

So, I have the 94 Explorer XLT getting more reliable every day. But problem still persists. Erratic idle at times (revved as high as 2000 the other day while my wife was in line at the bank drive through) and when it's cold, a popping back through the intake.

Could it be EGR? I noticed the vacuum fluctuates when it pops. I don't think it could be an intake valve leaking because it's done this for a long time and I figure by now it would have burned the valve.

What do y'all think?

 

[Anime]

Erratic idle is usually the Idle Air Control valve or IAC. Mine has done some pretty odd things at idle when it was a bad IAC valve, including revving high and sometimes making a rather unique "whistling" sound.

You can try removing it and squirting air intake cleaner in there, letting it drain out, and repeating, working the plunger mechanism with a finger as well to unstick it as much as possible. Sometimes it helps, sometimes you just need a new IAC.

You might want to check the air intake tube for cracks or holes, they can get brittle with age and get cracks at the flexy parts, or holes around hot spots like where the tube gets close to the radiator or radiator hoses. Check the vacuum caps on the drviers rear of the upper intake to be sure they aren't old or cracking and leaking as well.

 

[parris001]

Thanks. Yep, have done all of that. New IAC, even new air intake tube. All the vacuum ports on the rear of the intake are good.

Just replaced the EGR and it's solenoid valve.

KOER I have no codes, but KOEO I have a 335 and 214. The DPFE sensor is fairly new. Where is the EEC so I can check the wiring?

 

[Anime]

The ECM/PCM is located behind the passenger side kick panel.

You might want to pop off the ECM/PCM cover and check the condition of the capacitors, they get old and can leak and damage the board, giving engine codes and erratic operation as they slowly leak electrolyte and corrode the circuit board.

http://tinkerandfiddlewith.com/ranger.htm

 

[RustySJohnson]

Check the alternator

I know it's hard to draw a line between a high idle and the alternator, but it happened to me.

Just randomly, my Explorer would start revving high, 1200rpms if my memory serves me right. Not the 2000 you're describing.

It ended up being the bearing on the pulley side in the alternator was bad causing hi revvs to charge the battery.

 

[parris001]

UPDATE........

It turned out to be a bad EEC. I guess in closed loop it was running like crap but in open loop it was running fine. I found a good used EEC on ebay and she runs like a champ now. Thanks all for letting me bounce ideas off of you.

 

[parris001]

The ECM/PCM is located behind the passenger side kick panel.

You might want to pop off the ECM/PCM cover and check the condition of the capacitors, they get old and can leak and damage the board, giving engine codes and erratic operation as they slowly leak electrolyte and corrode the circuit board.

http://tinkerandfiddlewith.com/ranger.htm

Thread bump. I don't know how common of a problem this is, but I haven't had another single problem since changing the ECM/PCM. I should buy Anime lunch or something........ How long ago did I do this fix? Looks like April of last year. Yep. Sometimes you can get good advise on here..........