Hey, it's been a while since I've posted, but I just got the truck scanned, and I've got some codes that I've found on here, but most are on OHV's. I've got codes P0300, P0171, and P0174. I've read on here about the PCV valve, but that seems ok. I was gonna get a new coil, plugs and wires because they're original still and have 120000 miles, but if I don't have to I don't want to throw the cash because I have to redo the brakes on all four corners. I've gotten the 4.0 cover off of the intake and unplugged the TPS, and that didn't seem to do much. I also unplugged the MAF and it kicked right up to where idle should be and run fine, but when it was plugged in, it bogged down again. I've also removed the pipe from the PCV valve to the intake hose, and it just about stalls, so I'm leaning towards a bad MAF. My air filter was wicked dirty when I checked yesterday. There is also a terrible hissing under the hood, don't know if that's related or not. So thanks, I appreciate it.

 

the hissing means you have a vacuum leak somewhere...check the hose that leads from the air inlet tube to the pcv valve theres a good possibility it split