Here we go, I have a 98 explorer 4.0 sohc with 136k cel light flashed pulled codes read misfire cyl. #1,4,6 and lean. changed all 6 plugs and wires used motorcraft, cleaned mas, and checked coil pack(good) reset code. still flashes and reads misfire #1 and 4 and lean in both and idols rough. any ideas? thanks matt

 

Did you clean the IAC?? They seem to cause alot of the same type of problem, when they go bad they dont throw a code but can cause another code to be thrown. I had a code for misfire on #1 New plugs and wires no luck :<((( then I cleaned the IAC and it fixed the problem! Search for a recent thread on cleaning the IAC.

 

just cleaned IAC, noticed with old plugs and wires I would get 18-22 MPG now I get 10-11MPG. before i changed plugs CEL would just light up, now it flashes for along time. any more ideas? thanks.

 

Any new codes or the same ones. have you cleaned the MAF? the changing of plugs and wires did not cause your mileage to drop, the problems you have are. Have you checked the IAC resistance. Cant find the thread but there has been a recent one on cleaning the IAC and its resistance values. looks like cleaning it has made some difference, it may actually need replacement. Before throwing parts at it check the resistance values

 

Matt, this problem didnt start when trying to replace you pcv valve did it? Just noticed a previous thread on looking for you pcv valve.