Hey guys, long time lurker, first time poster. Well I have a 1993 Explorer with the 4.0 motor in it. A few months back it started having problems with surging and then dying while going down the road. So I read the message boards and since my sending unit for the fuel gauge went out, I decided to replace the fuel pump. When we got it back together Saturday it ran like a new explorer, no surging, dying and me no cussing. Well we drove it about 200 miles with no problems and I got in it this morning and the problem started all over again. I went and replaced the fuel filter and fuel regulator. So i went for a drive again and it drove great, but when i got back in it to come home it did its thing again. I then went and replaced the air temp sensor, MAF, and new plugs and wires When I hold the gas pedal to the floor it doesnt immediatly die, it bogs way down, like sucking more air than anything, then dies. I'm stumped.. Last things that i could replace would be the TPS and o2 sensors. When i come to a red light it idles funny like it wants to die but doesnt. And when i give it gas when it want to die it make this real bad knocking sound. Thanks in advance

 

[sm=welcomesign.gif][hr]Try to swap the fuel pump relay with the a/c relay in the power distrubtion box under the hood these fuel pump relay's go bad.

 

If the relay was bad wouldnt the pump not work? Or would it just be intermitent?

 

It could be intermitent.[hr]Somtimes the electrical contacts go bad and will not allow full current.

 

ok thanks, ill try that. be back in a few

 

Ok same problem even after changing the relay. If I unplugged the IAC should or shouldnt it idle funny? And i also unplugged the TPS and it had no change on the motor.

 

If any of the sensors were bad the check engine light would be on .[hr]Is the check engine light on?

 

It does come on. Sorry i didnt mention that. The night we drove it around no CEL came on. Today it came on, i had taken it to Auto Zone to get a tester put on it, they said it was my MAF, Air Temp Sensor and o2 sensors. I replaced the first 2 but called a shop about the o2's, they said that if the o2 sensors were messed up that it would act up almost immediatly. Im stumped on this one

 

That may be it then.[hr]If the computer is telling you the part is bad it usally is.[hr]I would replace the o2's and see what happens.

 

Thanks, im going to replace them this week and see if i stop cussing or not, ill get back with ya on it.