Big trouble

[Jar Head Joe]

I have a 1999 Ford Explorer XLT 5.0 AWD - 274,000 miles

I recently started having issues with it running really rough (erratic idle, lack of power and no top end speed, could not go faster than 35mph) and the CEL came on, I received trouble codes:
P1130 - O2 Sensor
P0455 - EVAP leak
P0304 - Misfire on cyl #4
P1401 - DPFE sensor
P0171 - Lean, bank 1
P0174 - Lean, bank 2
P1150 - O2, bank 1
P1151 - O2, bank 2

I still had the factory spark plugs and wires in it!​

So, it being 15 years old with 274,000 miles on it, I was not about to tackle that nightmare, I took it to Pep Boys for them to deal with it. They did a fine job getting the old plugs out.

I also replaced the EGR, DPFE, both pre-cat O2 sensors, MAF and the plugged factory fuel filter (which I was surprised the thing was even running). Checked the vacuum lines (no detectable leaks).

It ran like a dream... but after about 400 miles, it started to have sporadic rough idle issues, no CEL or trouble codes.

Then yesterday, I was driving, it 'chugged' a bit, then stalled... I tried to restart it every 5 minutes (in -8 degree temps by the way), and nothing, after about 45 minutes, it sounded like it wanted to fire... after about the 7th time, it fired up, ran rough, then stalled, it did this two more times, then I tried again, it started, idled rough, but kept going, so I revved it (floored it), idle dropped back to about 750 rps's and ran like a dream, and I drove on... Still no CEL or error codes.

What could be causing this inconsistent issue of rough idle and stalling?​

 

[arco777]

Welcome to the forum! Try posting in the second gen forum instead. For some reason this section of the forum doesn't get much traffic.

 

[Jar Head Joe]

Thanks!

 

[Runnin'OnEmpty]

Given the higher mileage on the truck, and the
absence of any codes, I'd suspect the fuel pump.
Maybe do a fuel pressure check to confirm...