So I've got a 96 ranger 172,000 on the clock. I bought the truck 8,000miles ago and I was driving it at work last Monday, when I noticed randomly at any speed that occasionally it would do this thing where after maintaining a constant speed for a while the engine would suddenly lose power and chug like crazy until I put the pedal to the floor and it would go back to normal for a while. When I got home I popped the hood and looked didn't see anything immediately wrong I figured I got a batch of bad gas or the fuel filter was saying goodbye. Unfortunately it rained most of the week here and I didn't get a chance to really dig into it, by Thursday the check engine light was on and it was doing the same thing (I should note that during this time I never had any issues starting the truck) and it started to idle rough at stop lights intermittently until I floored the pedal and it would go back to normal again, the gas milage seemed to be getting worse as well. By the afternoon I had refilled the gas from empty from somewhere else and was driving about 30mph when suddenly, engine just looses power and when I try to give it gas it just conks out completely on the spot and I rolled it to a stop and it wouldn't restart. When you turn the key it always will cough one time right at the stop and then just crank and crank and won't cough again until the battery dies. I happened to break down about a mile from an auto parts place so I replaced the fuel filter on the side of the road since I had the tools on me, no go, nothing so I had AAA tow it to my house. I borrowed a code scanner which came up with the following:

P0133
P0402
P1131

From what I can tell the fuel pump is working I can hear it come on when I turn the key. The car has new plugs and wires put in about 5k ago. I didn't see any obvious vacuum leaks but it's hard to tell without being able to run the engine, however the large intake tube between the air filter and the engine was very loose, tightened it, nothing. The from what I'm reading codes seem to suggest a problem with either the EGR or DPFE, however is seems like from what I've read most of those issues are more likely to cause the engine to run rough, but shouldn't keep the engine from starting at all. Before I start throwing parts at it does anyone have any suggestions as to try first? I tried to remove the EGR to clean it but with it's proximity to the firewall I'm having a hell of a time getting the nut on the lower vacuum pipe loose with the amount of clearance I have in the engine bay and I'm a little bit scared of twisting the pipe and ******* it up trying to get it off. Any help would really be appreciated. I'm not really a car guy, but I do most of my own repairs out of being a cheapskate and not trusting most mechanics. I'm ok with just about anything apart from digging into the engine or self or changing a transmission and stuff like that at which point I would take it to a shop.

 

P0133 - O2 sensor is not changing as fast as it should
P1131 - O2 sensor is still showing lean burn after more fuel is added

O2 sensors are speced to last about 100k miles, so I would change yours, just the front one by exhaust manifold, the rear O2s tend to last a lot longer.

O2 sensors use a chemical reaction to detect Oxygen, when the chemical coating starts to wear out it switches slower and they tend to fail lean.

P0402 - EGR(exhaust gas recirculation) system problem.
There are 3 parts to this system.
EGR valve on the intake
EGR controller/modulator
DPFE sensor

I would start with the EGR valve, p0402 means valve is open when it shouldn't be so that is what is causing the hard start and stalling.
First remove the vacuum line on the EGR valve and try to start the engine.
If it starts and idles OK, then EGR Controller is most likely the problem, it is sending a vacuum to EGR valve all the time so valve never closes, follow EGR vacuum line and it will lead you to the EGR Controller.

If engine still doesn't start you will need to pull off the EGR valve and check that it is not stuck open, it could just be clogged up with carbon and a good cleaning will get it working again.

The DPFE sensor is what is telling the computer to set code p0402, so it is probably OK since engine is running poorly

 

Just read this thread and was curious what your final fix if any turned out to be????

 

Traded for S10

 

Hope you got some money in your pocket with that trade.

If not then as Clint Eastwood said, "if he traded you even Sister, then you won't be seeing that fine gentleman in heaven"