I purchased this vehicle last week. 89k miles on it, and everything looked and ran fine. The other day, I noticed the "drain water separator" came on, so I got under the truck, drained it for a minute, and closed it. After driving for a few minutes, it came on again, so again drained it. After doing this like 5 times, I thought maybe the sensor is going bad and it keeps coming on. Yesterday, driving around the Wrench light came on, and the truck wont rev above 2500rpm or so. It will cruise on the interstate at 65-70, but if you go to pass it will downshift and stay at 2500 rpms and not accelerate or anything. I put a code reader on it, and no codes were found which I thought was strange. Also, if I try to set the cruise, it will not activate.

Any thoughts? I seen on other post people were mentioning the turbos or fuel system.

 

Truck is in limp mode so the cruise will not work.

Your code reader maynot be able to read the codes, depends on the reader you have.

There will be codes stored. Fuel system is fragile but it appears you may have more going on then a sensor.

Ensure your maintance is up to date...fuel filter changes and take it in to have it read.

 

I changed the fuel filters yesterday. I changed the top one first, looked almost new. Changed the bottom one, and it was pitch black and had chunks of stuff in it. I'm disappointed in the dealer, they told me everything was changed.

 

I would pull the lower one again and have a look. Check the draining of it again as well.

 

When you were draining the fuel pump did you see any water in what was drained?

 

No I didn't see any water what so ever in the fuel, which made me think it was a sensor, but that wouldn't make the truck go into limp mode would it?

 

I don't think it would go into limp mode for the sensor.

If you verify all is ok with the filters and stuff then I would certainly take it in and have it read.

If the fuel/water separator drains easily then it is probably not gunked up either. If the light is no longer coming on then it maybe due to another issue.

 

It drains just fine. Both the fuel filters are brand new so I know they are fine.

 

Describe chunks...... Sounds like the tank could be contaminated, did the fuel run clear?

 

I'm not sure how to describe it, just little pieces of trash. The filter is terrible looking. The fuel coming out is clean, but when we took the filter out of the housing, it was milky colored and even the plastic reusable cover had stuff built up on the inside.

 

If you bought this from the dealership and your bottom filter was as bad as you described, I'd take it with me to the dealership and ask them why you were told all maintenance had been done on your truck and you found the lower filter in this condition.

 

Yeah, sounds to me you have either a fuel or maintenance issue. Either way, not good that the truck went into limp mode, with any luck it's something small and unrelated. If not this could get ugly.

 

Went yo the dealer today. Showed them the filter and they took care of it. They put the code scanner on truck and found nnumerous codes. The problem was though, when they were having it cleaned for me, the people left the stereo on and it has after market everything and the amp drained the battery. They jumped it off and supposedly that's what set the truck codes off. Also with the filter that bad, it kept setting the "water in furl" code. Since having everything reset, it hasn't acted up again.
Complete change of subject now, what are some of the first things I should do to the truck to help it?

 

You should flush coolant, flush trans oil and change filter, change rear oil, change steering fluid. All this will put you on a known schedule. Added, also change the transfer case oil.

 

I planned on doing all of that, so I know everything is fresh in the truck. I was talking more along the lines of ERG stuff, exhaust, tuners? I was reading that doing a ERG block off and exhaust and tuners have shown great improvements in MPG on the 6.4 and that it actually helps the engine?