mountainsledhead

The other thing I noticed this morning is that the heater isn't blowing hot air, so I got out and checked and the heater hoses are hot, so I am wondering now if I have a vacume leak, maybe the heater blend door isn't moving which is causing it to blow cold air. Also now that you mention the brakes, they feel very stiff and grabby, if that makes sense, anyway they aren't working as they should, I just figured it had something to do with the ABS light being on, but maybe not huh?? Also the steering wheel is hard to turn, but I just figured that was because it was -6 degrees the last few days here.

I did notice that I have more blowby than I used to. There is enough that the front axle is covered in oil residue from the crankcase vent. I didn't even think of the vacum pump being a problem. How would I diagnose the vacum pump?

I will be taking the truck into the shop on thursday, to have them pull the rest of the codes and check fuel pressures. I really don't think that it is a boost leak, because of the lack of black smoke, also maybe I should describe this hissing sound a little better, it sounds more like a vacum leak, like mabey a heater control vacum line is cracked. and it will only happen when the I rev over 2300 RPM's, it is not dependent on load or speed, because it will do it when sitting still in neutral. This is all very good advice and I appreciate any and all thoughts or ideas on this issue. If anyone has anymore ideas I would love to hear them and get this thing figured out because it has me baffeled.

Boost leak was my first thought too, but I couldn't see/feel/hear any leaks in the intercooler boots. I'm starting to think that mabye it is in limp mode??

Unfortunatly, I don't have a boost gauge or EGT on the truck yet. They are now on order along with a fuel pressure gauge.

Ok, so here's the deal. I took my truck on a 1200 mile round trip to see family for thanksgiving, and on the way there the truck ran great. I averaged 19.67 MPG, but I was empty and not pulling a trailer. So then on the way back I was pulling a 24 foot flatbed trailer hauling a steel flatbed that I am going to put on my truck (weighs a couple hundred pounds). The truck had no power and got 10.32 MPG on the return trip. Also the ABS and BRAKE lights are now on and when I rev above 2300 RPM's I can hear a hissing noise from behind the dash, it sounds like it is comming from right behind the airbag on/off switch area, but it is hard to tell for sure (also it makes this noise even in neutral revving the engine).I also noticed that I was getting no black smoke at all, not even when I would go into a long hill and push the throttle all the way, it almost feels like I don't have any throttle after 3/4. I was having to down shift, and barely dragging over the top at 45-50 on hills that I usually pull in 5th at 70-75. So I stopped and looked things over and found nothing obvious wrong, so I unhooked my van aken chip to see if that changed anything, it didn't seem to make any difference, actually maybe a little less power if anything.At first I thought that I wasn't getting any boost pressure (I don't have a gauge on it), but if that is the case I should have black smoke. It feels like it isn't getting enough fuel maybe.Any ideas of what I should be looking at would be greatly appreciated, because I have to take it again this weekend on a snowmobiling trip.Thanks in advance Oh, I also pulled the codes and only got a P1693 code, I can't get the cheap code reader that I borrowed to show the companion codes that would go along with the P1693 code.