Illegallydead
Member
- Joined
- February 19, 2008
- Messages
- 15
- Reaction score
- 0
- City, State
- Centennial, Colorado
- Year, Model & Trim Level
- '01 Explorer Sport
Hey all. First post (I think
). My Explorer has been having issues lately, and was hoping someone could help me out. The only thread I could find similar to this was on a '91, so I am starting this thread. Sorry this is so long winded; just trying to thoroughly describe the problem.
The Car: 2001 Ford Explorer Sport (2 door) 4WD, 4.0L V6, ~83,000 miles.
When it is happening:
After driving the car for extended periods on hot days, the problem starts. This has happened three times - first, after 25 miles, outside temperature ~95°. Second, roughly 50 miles, temperature nearing 100°. Today, roughly 55 miles, temperature ~95°. The issue did not appear after driving about the same distance at night. The car drives just fine shorter distances around town. It occasionally shifts roughly, though that is kind of normal...
Symptoms:
The car starts out driving fine. After running for a while (usually ~1/2 way into the trip), the engine starts to feel sluggish at higher RPMs. If I let it get below 2000-2300 RPM (roughly), the car starts bucking; power cutting in and out, regardless of speed. From low speed or a stop, if it has only been doing this for a while, I can generally punch the gas, let it lurch a few times, and get up just enough speed to where it can get above 2000-ish RPMs and be able to run without the lurching/cutting in and out.
If it has been doing this for a while (as it was today), the car will not idle well at a stop. It will rev up and down on its own (down to 200, shoots up to 1200, back down, etc.) and will usually die. The first time this happened, I was able to start the car up again just fine (though the issue persists). Today, 2 out of the 4 times it died trying to get it off the road, the engine would not crank at all (not even trying to…). I had to pull the key, wait a bit, and try again.
The first time it happened, it worked just fine after sitting overnight, no issues at all on the drive back. I am letting it sit for ~4-5 hours tonight, hoping it will sort itself out again.
No gauges are out of normal range, except the battery gauge appears a little low when this starts happening (I think)
After the second incident, after driving around town a while, the computer threw codes P0171 & P0174 - Left and Right Banks both running lean. I can get post the freeze-frame readouts if any of that data might help.
Info on the car / things to consider:
>Recently removed the stock air filter and box, and put on a higher-flow Spectre cone filter & MAF sensor mount. The issue started after this (happened the first two times with the new set up. Returned to stock setup. Drove fine for a while then the third incident happened). This is certainly the low hanging fruit, could be the MAF sensor is going bad...
>I poured in a bottle of ISO-Heet last fill-up in case there was water in the fuel. Did not solve the issue.
>The transmission was overhauled 25,000 miles ago, due to the first gear / reverse cog being stripped.
>Replaced plugs and wires 10,000 miles ago. Had a hell of a time installing one bank, so ran for ~50 miles with 1/2 new plugs, 1/2 old plugs before completing the install.
>The radiator thermostat was replaced and the fluid changed 4,000 miles ago, due to a busted thermostat.
>The fuel filter was replaced about the same time as the thermostat.
>The battery was replaced by the previous owner 40,000 miles / 5 years ago.
>I have changed the oil regularly, and switched to synthetic 3 changes ago.
>No scheduled maintenance that I am aware of (no records from previous owner, and I have not done any yet)
I would very much appreciate any suggestions anyone has. Thank you so much!
At least it drives fine around town (for now), so I can still get to work…

The Car: 2001 Ford Explorer Sport (2 door) 4WD, 4.0L V6, ~83,000 miles.
When it is happening:
After driving the car for extended periods on hot days, the problem starts. This has happened three times - first, after 25 miles, outside temperature ~95°. Second, roughly 50 miles, temperature nearing 100°. Today, roughly 55 miles, temperature ~95°. The issue did not appear after driving about the same distance at night. The car drives just fine shorter distances around town. It occasionally shifts roughly, though that is kind of normal...
Symptoms:
The car starts out driving fine. After running for a while (usually ~1/2 way into the trip), the engine starts to feel sluggish at higher RPMs. If I let it get below 2000-2300 RPM (roughly), the car starts bucking; power cutting in and out, regardless of speed. From low speed or a stop, if it has only been doing this for a while, I can generally punch the gas, let it lurch a few times, and get up just enough speed to where it can get above 2000-ish RPMs and be able to run without the lurching/cutting in and out.
If it has been doing this for a while (as it was today), the car will not idle well at a stop. It will rev up and down on its own (down to 200, shoots up to 1200, back down, etc.) and will usually die. The first time this happened, I was able to start the car up again just fine (though the issue persists). Today, 2 out of the 4 times it died trying to get it off the road, the engine would not crank at all (not even trying to…). I had to pull the key, wait a bit, and try again.
The first time it happened, it worked just fine after sitting overnight, no issues at all on the drive back. I am letting it sit for ~4-5 hours tonight, hoping it will sort itself out again.
No gauges are out of normal range, except the battery gauge appears a little low when this starts happening (I think)
After the second incident, after driving around town a while, the computer threw codes P0171 & P0174 - Left and Right Banks both running lean. I can get post the freeze-frame readouts if any of that data might help.
Info on the car / things to consider:
>Recently removed the stock air filter and box, and put on a higher-flow Spectre cone filter & MAF sensor mount. The issue started after this (happened the first two times with the new set up. Returned to stock setup. Drove fine for a while then the third incident happened). This is certainly the low hanging fruit, could be the MAF sensor is going bad...
>I poured in a bottle of ISO-Heet last fill-up in case there was water in the fuel. Did not solve the issue.
>The transmission was overhauled 25,000 miles ago, due to the first gear / reverse cog being stripped.
>Replaced plugs and wires 10,000 miles ago. Had a hell of a time installing one bank, so ran for ~50 miles with 1/2 new plugs, 1/2 old plugs before completing the install.
>The radiator thermostat was replaced and the fluid changed 4,000 miles ago, due to a busted thermostat.
>The fuel filter was replaced about the same time as the thermostat.
>The battery was replaced by the previous owner 40,000 miles / 5 years ago.
>I have changed the oil regularly, and switched to synthetic 3 changes ago.
>No scheduled maintenance that I am aware of (no records from previous owner, and I have not done any yet)
I would very much appreciate any suggestions anyone has. Thank you so much!
At least it drives fine around town (for now), so I can still get to work…