a few questions..

[clvineyard]

i have a 93' explorer with the 4.0 and i have had an ongoing problem since i've owned it. when it's cold it starts up and runs awesome then ill drive to the store,go in, go out, get it and start it, and it will start it will sound like it's gonna die and sometimes it does and it runs like crap until you get it up to like 3,000 rpm it dosent do it every time but 75% of the time it does. and one day i opened up the hood when it was happening and i manually gave it some throttle and it like about shot my airbox off the throttle body, so im basicly clueless and im not getting any black smoke so i have no idea. im also getting about 195 miles to a full tank so im clueless any help would be great

 

[ma96782]

Pull codes??

Aloha, Mark

 

[marragtop]

Yep, pull the codes. Even if the CEL is out it can still have codes stored. Most Autozones will pull them for free. Call ahead to verify.

 

[clvineyard]

well i went to autozone and they said it was a 13 which is clear, and my light isint on, so i have no clue i replaced my plugs and wires, and fuel filter and my air filter still doing the same damn thing

 

[l1k2gadd]

I troubleshot a bad Throttle Position Sensor in my mom's E150 Club Wagon XLT Van for months before I got a failure code on it. Her idle would jump up while she was slowing down at red lights and stop signs at no given time with no warning. For months it did this. I changed things under the hood and in the fuel system because I was getting no failure codes. Messing with her van one day I started, shut off, tested for and cleared codes (none), started, shut off, tested for and cleared codes (none) and then one time it failed and failed as a primary failure code. I changed the TPS and that did it. Just because the vehicle is having problems doesn't necessarily mean you will see failure codes in a diagnostic test.

I don't understand the description given in my El-Cheap-O Code Scanner book for a failure code 13. From your description it sure sounds like something is causing a backfire for the air box being blown off the throttle body.

 

[MrShorty]

well i went to autozone and they said it was a 13 which is clear,

I've never trusted the people at Autozone to pull codes on these. I suppose it's possible they are using some kind of special scanner that offers its own interpretation of the codes, but I don't know.

1st obvious error: A standard EEC-IV code of 13 does NOT mean all pass, it has to do with the IAC valve. 2nd, your '93 should be outputting 3 digit codes. So, a pass code on your '93 should be a 111. I would try pulling codes again and verify that you are getting a pass code or not. You might review my notes on pulling EEC-IV codes thread (and associated references) and see if you're up to doing it yourself.

Another thing to look at would be fuel pressure. When it's hard to start is it low? high? Will the fuel rail hold pressure when the pump isn't running? Any fuel in the vacuum line to the FPR?

 

[clvineyard]

well what i did was i started looking around the engine compartment, and i looked at my idle air control valve and i unpluged while the engine was running, and it dident do anything different, then i drove it down the road, it drove the same as it always did, even with it plugged in. so i mean when you unplug it, it should run way different right? i dont know im lost

 

[clvineyard]

well i have no idea if this has anything to do with it, but i just found a bad upper intake manifold gasket, i have no idea if this is contributed to it at all i dont know, is this a difficult repair, i have it patched with blue rtv sealant for a few days and it's holding so any help would be great

 

[StillKicken]

well what i did was i started looking around the engine compartment, and i looked at my idle air control valve and i unpluged while the engine was running, and it dident do anything different, then i drove it down the road, it drove the same as it always did, even with it plugged in. so i mean when you unplug it, it should run way different right? i dont know im lost

If this helps....

I cleaned my IAC valve the other day. I forgot to hook the electrical connector back up and went to take it for a test drive. I cranked it up and it loped real low. The rpm's sank to about 600. Never died. You could see the voltage gauge dropped to almost the L. Drove it, drove fine. Just when came to a stop. Rpm's dropped back down to 600 and battery gauge dropped again. Got scared I messed something up. Got home, checked it out, saw connector still undone, hooked it up....fine.