So my buddy has a 96 F250 PSD with 278,000+ kms that has recently developed a rather puzzling issue. The truck is modified (baby swamp injectors, MBRP DP+exhaust, AFE intake, TS chip). It started a couple of days ago with the truck losing power (pedal to the floor with no motivation to accelerate) and the check engine light came on. This occurred a few times and got worse over the course of the day with the truck outright dying like someone turned off the ignition. When this started happening he set his chip back to stock with no changes to it acting up.

We pulled the codes and it was for the CPS sensor. Ordered it and had to wait a day for it to show up. This is where things start to get interesting. We changed the CPS this afternoon and on initial start up the batteries were dead. A quick jumpstart had it running but the engine was loping. After shutting the truck off and restarting it, the loping went away (other then this the truck has no issues idling properly). However shortly into the test drive it started acting up. Check engine, loss of power and the engine dying like it was being shut off. Stopped at our local auto shop and had them pull the codes again. CPS intermittent is what it stated. Quick fix turned into several hours so we had to leave the truck parked out front of the shop for a couple of hours but came back to move it later this evening.

Again the batteries were dead, another jumpstart had it back up and running so my buddy figured since we were close to the fuel station to fill it up. I remembered that he had switched over to his front tank a day or so before all of his issues started occurring, figuring what the hell, fill up the rear tank and lets go for a short drive. With the chip set to stock and on the rear tank the truck drove for 20-25 minutes with no issues what so ever (up to highway speeds, full rpm pulls in different gears, etc). As we are getting closer back to the fuel station, interest gets the better of us and he changes it back over to the front tank and bumps the chip up to economy.

Within a minute the engine starts to run audibly worse, check engine light, loss of power and died as we turned into the station. To make sure it was not a fluke and to remove only other variable of the chip being turned up, we changed it back to the rear tank. With the truck restarted and chip still set on economy we cruised around for a bit more, the check engine light came back on but the truck ran fine with no lost of power or stalling. Turned the truck off to reset the check engine light, flipped the chip back to stock and still on the rear tank we set off again with zero issues until we parked it for the night.

Anyone have any ideas as to what the heck is going on with this truck at all? We checked the ICP connector for oil intrusion but it was bone dry. We will be going back to get the codes it threw checked tomorrow but I figured some people on here might have some idears?
Cheers!

 

Is the alternator charging? With it not starting that is where I would start looking.

 

Agreed. Without the proper electric/volts, it won't run right, or not at all.

 

Some more puzzling information, went out and started the truck this morning with no issue, truck loped for a second or two but cleared up and idled fine. Let the truck run for a few minutes before hooking up a volt meter to the battery cables, 14.9v constant. Shut the truck off and did a load test on the batteries, they also checked out fine. Truck was left on the rear tank and the chip set to stock.

Changing the oil and fuel filter (only 3,000kms since they were last done but it is starting to drop below 0 here) since we have to wait a bit before we can get the check engine it threw last night before we parked it checked.

 

Did you scan it ?