Never Ending Problem

[dmathews]

I have a 99 Explorer 4.0 SOHC with 181,x.. miles on it. Here for the past 6 months I have been pulling the codes P171 and p174 which where running to lean. When I stomp on the gas it would rev to about 4k and just sit there, wouldnt accelerate or nothing and there is a loud sucking noise coming somewhere from the intake. It sounds like its coming from the IAC valve. I have cleaned that, I have replaced the upper and lower intake gaskets, I have replaced the fuel pump and fuel filter, replaced the O2 sensors, plugs and wires, cleans the MAF and new filter, cleaned the intake. I have done everything but still the problem continues. I was told the sucking noise would be cause from the computer thinking it was getting more fuel when it doesnt so it sucks in more air. With my car started and no hoses or nothing like that removed the fuel pressure was 40 and when u pull on the throttle it would drop to about 30 or below... So that seems to be my problem but idk if it is my fuel pump or my fuel regulator or what it is... I am starting to hate to, just payed tonight to have the gaskets put on and it didnt fix it... And now I have a slight vibration in my gas pedal it anyone knows that that is from... Any help would be very very appriciated.

 

[1998Explodasport]

I think your fuel pressure is supposed to be between 35-45 psi so if it's dropping below 30psi I would look into replacing the fuel pump or at least start with the fuel filter. I am not 100% on those fuel pressure numbers though.

I used to have a 98 SOHC so let me see if my alldata is still good and I will try to get the correct fuel pressure for you.

 

[1998Explodasport]

I couldn't log on, my account expired but if I remember correctly the fuel pressure was supposed to be between 30 and 45 psi.

 

[dmathews]

yeah i have searched but the mechanic told me the pressure should be about 60 at idle and 75 when accelerating, something about right after 98 the explorers didnt have the return gas light so it bumped the pressure readings or something, idk though

 

[1998Explodasport]

If you have a returnless fuel system then your fuel pressure should be around 65psi.

 

[dmathews]

yeah so i am guessing the fuel pump... The one that i put in it must have just be a bad one or something, I bought it from ebay like a dumbass but other members have and have had no problems from the same seller.... If I put the money into it and get the pump and it doesnt fix it, im catching it on fire, lol

 

[1998Explodasport]

Ya, you have to be careful with cheap fuel pumps, sometimes you get lucky and most of the time your not. I put an Airtex fuel pump in a GMC Savanna 3500 and 2 days later I had to replace it again. Don't feel bad I am having alot of trouble with my Ex. Good luck with yours.