98 Explorer 4.0 ......... she quit on me, can yall help me out

[CS925]

Hi everyone, amazing people and amazing help in this forum. Huge community. Love it. Having a massive issue on my 98 explorer 4.0 v6.

A week ago I noticed when I would quickly floor the gas pedal, it would bog down. But when I slowly accelerated it would get going no problem. Then the next day it sputtered and died when I gassed it from a stoplight. Left me stranded in the intersection. I pushed it to a parking lot, and it will start and run but then sputter and die. I might even be able to drive it for a day or 2 but it will do it again.

From phone calls to Meineke, the gas station mechanic and my friend, I dont know where to start. Possible issues I think could be related :

--- About 3 weeks ago I changed the spark plugs and wires, and im pretty sure i disconnected a vacuum hose back behind the engine. I can really hear it. But cant find it. When I turn the car off I can even hear it but eventually hisses itself quiet.

--- I have been driving around with a P0153 (bad o2 sensor) for about a year, and one mechanic said this could be the culprit, another one said no way it wouldn't cause this big problem.

--- about a month ago I installed a new fuel filter, and ran 2 bottles of techron fuel injector cleaner through the tank with only a few gallons of gas so that it really cleaned things out.

--- possibly the coil pack? but one of the mechanics said no the car wouldnt even start, which it does.

I guess at this point I should replace all 4 of the o2 sensors, replace the fuel filter again, replace the fuel pump ? what about that vacuum leak?

Thanks so much if anyone can help me out I really appreciate the input/ help in which direction to move in.

 

[Tech By Trade]

Clogged cat?

 

[CS925]

or fuel filter, fuel pump or vacuum leak ? one of those more so wouldnt you think ? I have no idea.

 

[koda2000]

Fuel pump, fuel filter, MAF, TPS, DPFE, EGR. Hard to say. Do you know for sure that the only ODB II code you currently have is the P0153 or are you assuming? Which 4.0 V6 do you have? if it's the SOHC engine it could be something more serious. You're going to need to do some diagnostics to narrow down the possibilities.

 

[CS925]

Fuel pump, fuel filter, MAF, TPS DPFE, EGR. Hard to say. Do you know for sure that the only ODB II code you currently have is the P0153 or are you assuming?

For sure its P0153, and thats the only code nothing else. Had that code for awhile now.

 

[ranger7ltr]

I would start with checking fuel pressure no matter which engine you have... In the 98 MY the fuel pressure should be 35-43 psi with the engine running and a vacuum source on the regulator...The pressure will be higher with the vacuum line removed...

The first part of the problem tells me you have a fuel pressure/delivery problem... "A week ago I noticed when I would quickly floor the gas pedal, it would bog down. But when I slowly accelerated it would get going no problem. Then the next day it sputtered and died when I gassed it from a stoplight. Left me stranded in the intersection. I pushed it to a parking lot, and it will start and run but then sputter and die. I might even be able to drive it for a day or 2 but it will do it again." This is a classic fuel issue...If the fuel that came out of the fuel filter was dirty, muddy, coffee looking you probably have rust in the tank and a dead or dying fuel pump...It is not delivering enough fuel to keep your engine running like it needs...And the vacuum line could be one to the heater control valve or the line to the vacuum canister for the HVAC system... They are both on the passenger side/middle of the back of the firewall area...

But if you are working on this truck please verify the problems before throwing parts at it... If a shop is working on it make them verify the parts changed and why the need to change them... BTW the P0153 code is an O2 sensor responding too slowly for the PCM to properly read it... It will affect the engine but not to the extent of it not running... It is Bank2, sensor1 that needs to be replaced...

 

[CS925]

I would start with checking fuel pressure no matter which engine you have... In the 98 MY the fuel pressure should be 35-43 psi with the engine running and a vacuum source on the regulator...The pressure will be higher with the vacuum line removed...

The first part of the problem tells me you have a fuel pressure/delivery problem... "A week ago I noticed when I would quickly floor the gas pedal, it would bog down. But when I slowly accelerated it would get going no problem. Then the next day it sputtered and died when I gassed it from a stoplight. Left me stranded in the intersection. I pushed it to a parking lot, and it will start and run but then sputter and die. I might even be able to drive it for a day or 2 but it will do it again." This is a classic fuel issue...If the fuel that came out of the fuel filter was dirty, muddy, coffee looking you probably have rust in the tank and a dead or dying fuel pump...It is not delivering enough fuel to keep your engine running like it needs...And the vacuum line could be one to the heater control valve or the line to the vacuum canister for the HVAC system... They are both on the passenger side/middle of the back of the firewall area...

But if you are working on this truck please verify the problems before throwing parts at it... If a shop is working on it make them verify the parts changed and why the need to change them... BTW the P0153 code is an O2 sensor responding too slowly for the PCM to properly read it... It will affect the engine but not to the extent of it not running... It is Bank2, sensor1 that needs to be replaced...

Thank you so much for the help, on saturday I fired it up again and drove around town with the hopes that it would die on me. Sure enough it did (luckily in a parking lot). I had my friend with me and I told her to cycle the key a couple times so I could hear if the fuel pump was priming. Nothing. About 15 cycles later, I heard the fuel pump prime and told her to start the car, it fired right up. I'll replace it this week So glad that ive found the issues I was worried.

I'll fix the o2 sensor while im at it. According the schematic that ford emailed me, there are 4 sensors and bank 2 sensor one is driver side, upstream can anyone confirm that please ?