In Dire Need of Help!!!

[ihatemyexplorer]

Ive used this forum before to answer some questions for myself, now I am in dire need of help solving a problem...

I have a 1998 Explorer Sport, 4.0 EFI, Six cylinder X engine, about 178,000 miles on it... In the past year I haven't had many issues, but now I am encountering a serious problem..

I will press the accelerator and get to about 25 mph, then lose all acceleration.. I have to back my foot off the gas, and then it slowly picks up speed, also cannot take hills.

I recently got the p0171 and p0174 codes, so I replaced the manifold gaskets, didn't fix the problem.. Within the last six months I have replaced the catalytic converter, all 02 sensors, fuel pressure regulator, Fuel pump, ECU, upper radiator hose, thermostat, front suspension, IAC valve, MAF sensor (from the local pull a part), inertia switch, the water valve, AC Bypass pulley...

Any insight into what is causing my problem?

 

[MFD70]

It might well be engine related, but a quick look at the tranny fluid level might be worth a try, I've had a couple of different 4X4's give me strange acceleration and hill climbing faults over the years due to low or bad transmission fluid.

 

[ihatemyexplorer]

Transmission fluid level is fine, checked that, however it is kinda discolored.. it looks like it is simply motor oil instead of the red color.

 

[MFD70]

Discolouration usually indicates overheated or burned fluid, can be caused by excessive heavy towing. I've only had my explorer a couple of weeks but over the years I've had a Jeep refuse to go into reverse, a Chevvy light the check engine warning , and Range rover that wouldn't go up a hill and a Rexton with severe transsmission slip, all these faults went away with fresh tranny fluid (although the Range rover and Rexton were swiftly disposed of before anything else went wrong!)

 

[ihatemyexplorer]

I'm going to change out the tranny fluid and throw a new filter in, no harm in doing so, and hope it does alleviate the problem, if not, I'll be back for more thoughts..

 

[ihatemyexplorer]

After replacing the fluid and filter, and also noticing I was low on oil, it shifts better, but the problem is still there....

 

[MFD70]

Looks like it is engine trouble then, still the transmission will work better for the fluid change.
I guess it's engine fault diagnosis time then !
Loosing oil, it it smoking ? Piston rings, compression issues ?
I suppose you've looked for oil in the coolant or white emulsion in the oil (head gasket leakthrough) ?
Then its plugs, leads and other spark related electrics.
Fuel pressure, bad fuel pump, blocked filter or lines.
I don't have any experience with the cologne 4 litre SOHC, but have had cars with the similar 2.8 V6 cologne or the old V6 3.0 Essex engines, the 3 litre was bomb proof ! As engine technology progresses, power and reliability increase but they get harder to diagnose once they do go wrong !
Keep us posted with what you find, this might be my first 4 litre remote diagnosis !

 

[ihatemyexplorer]

None of the above, I forgot to mention that the wires and plugs are new also, the fuel pump is just about a year old, but already whining like a dog that's been hit repeatedly... I think the old computer I had in there screwed with stuff so bad that it ruined the new pump, its on my list to replace again...

After reading more posts, I may still have a shot maf, or a bad cps... but I'm at the point where I'm about to stick a piece of tnt in the gas tank... it's going to the shop on Tuesday morning for a free evaluation, so if I find anything else, I'll post it..

 

[1998Exp]

For what it's worth: in all your troubleshooting attempts, have you replaced the fuel filter? A new pump whining sounds like it's fighting an obstruction, the most common cause of which would be a plugged filter. Pressure test may not detect the condition, because at low power the fuel demand is just a trickle.

None of the above, I forgot to mention that the wires and plugs are new also, the fuel pump is just about a year old, but already whining like a dog that's been hit repeatedly... I think the old computer I had in there screwed with stuff so bad that it ruined the new pump, its on my list to replace again...
...

 

[ihatemyexplorer]

The filter was new when I replaced the pump, I did remove it, and blow it out, and I have had intentions to replace it again, just keep forgetting to buy it.. I think I will get one tomorrow or the next day...

 

[ihatemyexplorer]

Okay, last night I cleaned the MAF, and today replaced the fuel filter. When I took it for a drive, everything was good, then later on it started acting up again, but the ecm finally put up a cel, so I will post the code(s) after I have the truck back from it's evaluation in the morning

 

[SparkyJeff]

clogged Catalytic converters?
Can you disconnect the exhaust pipes at the manifolds and drive the truck to see the problem is exhaust restriction?
Just taking a guess..

 

[ihatemyexplorer]

Ive replaced it already, spent four days cutting out the factory converter and put a magnaflow on..I listed everything I've replaced....

 

[SparkyJeff]

Ive replaced it already, spent four days cutting out the factory converter and put a magnaflow on..I listed everything I've replaced....

Alright, I'm just trying to keep it simple. You said converter, not converters. does that 4.0 have only one? IDK mine has a handful of 'em.
Plugs, wires, fuel pressure, air filter,
The fuel pump was replaced a year ago?? It's making noise?? Aftermarket fuel pump?? Those 'lifetime warranty' parts store replacements are worthless in my limited experience. What kind of fuel pressure does it have now?
I'm still just guessing..

 

[Tripod2]

Was there rust, or any other obstruction, in the filter? Cause if you replaced the filter and it ran fine for awhile, maybe something clogged it back up. Maybe a rusted tank, or something broke into the tank and is clogging the system up. Or it may even be a directional filter, make sure its facing the right way.

 

[Yankee516]

Did you pull the latest code? I read that you swapped the MAF for another used one and it ran fine then. Maybe if you have narrowed it down to something emissions related you can pickup some MAF cleaner and a new air filter. You can also try cleaning any debris out the intake between the filter and the MAF.

The MAF in my '94 was pretty dirty. Car hesitated whenever I hit the gas before finally "catching". On the highway, I couldn't get any torque and was barely able to go above 60 without it floored. MAF cleaner made it act like a WHOLE different car...especially with the throttle/kick-down cable mods!

I know how frustrating these situations can be, sorry for your problems and hope you get them fixed!

 

[ihatemyexplorer]

Not sure on fuel pressure reading, dont have a guage to test it, cant afford one riht now either. Cleaned the maf, going to swap it out with the other one I have tomorrow, still getting the p0171&0174 codes, also going to see if the pump is still under warrenty and if so, replace it again...

 

[Yankee516]

The codes you are getting could just as easily be the MAF as the pump. Seeing as the MAF is the easiest to do, just get a can of MAF cleaner and shoot it up real good. DONT let anything touch the actual sensor other than the stream of cleaner. Let it sit and dry for a while then reinstll it and give it a whirl.

If you still have a problem, then the pump/filter are another good idea to check. Maybe also make sure that your fuel lines aren't crimped anywhere under the car.

 

[ihatemyexplorer]

Fuel lines are fine, no crimps, no leaks.. like I said before, I'll clean out the other maf and go from there..

 

[ihatemyexplorer]

Haven't gotten to drop the tank, been too tired, but will get to that tomorrow. Just replaced egr valve and tube, other maf is in, and still acting up, all I have left is pump and regulator...