1999 Explorer with rich & lean codes.

[kujo112003]

I have a 1999 Explorer with 200000 + miles on it. I just had the head gasket and heads replaced. The check engine light was still on and the idol was rough, had the codes read, stated bank 1 & 2 were running too lean. I changed the mass air flow sensor. It fixed the rough idol but now it won't stay running while at a light and when I am driving steady, it will stick as if it's not getting enough gas and then jump and go. I had the codes read again, and now they say bank 1 & 2 run too rich. I changed the throttle position sensor as well. I am at a total loss and just can't afford to keep taking guesses. Does anyone have any idea what the problem may be?

 

[albi1cnobi1]

Bank 1 and 2 too lean could be an intake gasket not seated properly. Banks 1 and 2 too rich, along with the stalling at a light could be a stuck IAC(idle air control) valve. It is under the cover that screws to the upper intake. It's very easy to clean with a can of carb/throttle body cleaner. Unplug the electrical connector and remove the 2 bolts holding it on. If you look inside you'll see a plunger type shaft with a seal on it. These valves get choked with carbon. Just spay the heck out of it until its clean and the shaft can move freely. Bolt it back on, plug it in and give it a try. This valve controls air amounts into the system and if it's stuck closed you get more gas than air, hence the too rich codes. It will also cause stalling at idle(i.e. lights and stops). Try that and let us know.

 

[kujo112003]

Thank you so much. I am going to try that as soon as I get home from work tonight. Also, I really appreciate the detailed description, because I would have had no idea where that was....lol....I am just a girl...haha.

Thanks again and keep your fingers crossed for me.

 

[1Aauto]

Welcome to the site.

 

[albi1cnobi1]

No problem. Probably should have asked already but which engine V8 or V6?
I'll try to post a pic of it if you let me know which one.

 

[kujo112003]

I have the V6 OHV.

 

[albi1cnobi1]

Here is a thread with pics of the OHV engine. http://www.explorerforum.com/forums/showthread.php?t=84220. Hope that helps.

 

[kujo112003]

Wow...that's awesome. Thank you so much. I just hope that this finally solves the problem, I love my truck and that's why I have kept her, but I'm telling you, the last week or so...I have learned to HATE her!

 

[albi1cnobi1]

They're like dogs, they can sense that.

 

[kujo112003]

It is so funny that you say that. I have always talked nice to her, got defensive if anyone said anything bad about her, ya know. Yesterday, I called her a you know what and then just about every other word in the book too, I was so furious yesterday. As if there wasn't enough crap going on with her, the damn hood was stuck and I couldn't get it popped open...took forever....but, I swear she knows when I'm pissed and acts up more...that's just hilarious that you said that.

 

[kujo112003]

I'm very sad to say, I did it, but it did not fix my issue. Any other suggestions?

 

[BrooklynBay]

Welcome to this forum! I've renamed your thread, and moved it into the EEC-V section. What were the code numbers?

 

[kujo112003]

The codes were PO171 and PO172. Bank 1 & 2 run too lean and then too rich.