new to the forum - question

[snay502]

just bought a 2002 Explorer Sport Trac 4wd. Found you through google. good info here.

I have a slight intermittent surging / low idle while in drive and stopped at a light. Doesn't do it in park while idling. Threw numerous codes related to lean / rich.

I will check the PCV elbow tonight (good thread!). Of course parts store says MAF sensor.

Will try to clean that first before $92 dollar repair

 

[JacobDaniel]

Hi, my truck was doing something similar and I was getting about 8MPG.
I cleaned the MAF, checked speed sensor and all that.
Turned out to be both upstream O2 sensors.
in my first post "new members" I have a link that will show you how to make an O2 emulator for under $5. The emulator is just to see if the issue improves, if it does then you know the problem.
After using the emulator, I was getting 16 MPG (check engine light still on), after replacing the O2 sensors I get about 20 MPG and CEL is off.
Cheaper than the $80 O2 sensors each.
O2's normally last for 70 to 80K, mine had 170K when they went out.

Good luck