I went wheeling yesterday and ran into some issues.

The truck died a few times while driving, so I figured my CPS was going out. She would start back up immediately but after a while, the truck did not want to idle.

Once I left the park is when I started having real issues and getting Service Engine lights. The truck would not go over about 35 mph and ~2,000 rpms. If I tried to give it too much gas, it would bog down. So I pulled over and read the codes.

P1300- Random/multiple cylinder misfire detected
P1306- Catalyst damaging level of misfire detected on cylinder No.6
P1304- Catalyst damaging level of misfire detected on cylinder No.4
P0731- * Ratio monitoring, implausible 1st gear ratio.
P0103- Mass or volume air flow circuit high input | MAF signal > maximum threshold, which is speed dependent
P0174- System too lean (bank 2)
P0171- System too lean (bank 1)
P0300- Random/multiple cylinder excess emissions detected
P0304- Cylinder 4 misfire detected
P0306- Cylinder 6 misfire detected

I have been chasing misfire issues for a bit now. I have replaced plugs, both coil packs, and both upstream O2 sensors. Wires were upgraded by previous owner. I'm not losing coolant and plugs aren't wet.

Could P0731 be a bad XYZ switch? M&S lights were not flashing. Bad speed sensor? It was very muddy yesterday.

Thanks in advance.

 

0731 is a code that should light M&S lights (when happening) and if happens two days in a row turns on the engine light. TPS switch might be an issue. VSS is a D1 demon, in the D2 the four wheels are averaged by the SLABS for that data.

Water on old coils / spark plug wires?

 

Probably the MAF got muddy water into it.

 

Good point becasue the tranny talks to the engine and might conclude that correct gear based on calculations of engine load was way off.

 

I'm going to check it out this afternoon. I have a snorkel, but it's possible.

 

Remember that everything British leaks, and that works both ways. It could be too that you did get some water on the computer.

 

Turns out you were right. Thanks for your help!!

 

So, what are you needing to do, cause although your MAF took a hit, you do have other issues?

 

I ordered a new MAF and air filter and they will be in today.

I cleaned out the intake tube, seafoamed the engine, and I will be tracking down and sealing off where the mud entered in the first place.

I had a spare MAF that the previous owner gave me with the vehicle. I cleaned it with MAF cleaner and replaced my muddy one. All of the other codes (misfires, etc.) went away, but I got a new and different set of MAF codes. That told me that my MAF was the only issue and it was the cause of the rest of the codes.

Looking at the RAVE verified that the MAF could give me all of the codes I was having.

MAF.pdf

Thanks again everybody.