Hello guys,
The truck is a 1997 F250 7.3 with intake chip and tune. Chip is a TW and is always set to 50 hp cause the tranny cant handle any more. Recently I have noticed some odd issues with my truck and I can't help but think they are all caused by the same thing. Basically the truck was running like a top two weeks ago. I had new tires put on it (oversized from what was on it before at 285/75/16) and took a 3 hour trip to visit family. On the drive I began noticing what seemed like increased turbo lag and it completely looses boost through the gears. EGT's are higher than usual and it will smoke when I dog it which isn't a huge deal but it didn't used to so I believe it's related. The truck still makes 25psi of boost at WOT which seems decent but it just doesn't pull quite as good. My fuel economy has tanked. I was getting 17-15 and now I'm getting 10. This weekend I changed the oil and replaced the fuel filter because it was due and now the truck has a funny idle. Almost like a 50-100rpm variation every 15 seconds or so but not nearly that consistent. Now I know this is a lot of information but like I said I think it's all related. I am going to order Auto Enginuity this weekend as I no longer have a snapon solus and therefore can't do any diagnosing that way. Just curious if you guys have any suggestions or have seen this before. Thank you!

Edit: I wanted to add that the truck is nearing 270,000 and is mechanically all original.

 

Unplug your chip and give it a whirl.

 

I can try that this weekend. Just a PITA to get to on the OBS. You think the connection might be getting loose or something?

 

From what you discribe, Yes.

 

Could a bad fuel pressure reading have something to do with it? I noticed my fuel pressure sensor wiring is missing about 2 inches of insulation and is extremely frayed. Not sure when or how it happened but someone wrapped it up with electrical tape and the tape has come off. I'm going to repair it this weekend. Just curious what you think.

 

Never mind it's the restriction sensor sorry.