Pull the airbox out of the truck, open the throttle body, look down in the intake with a flashlight. If you see oil pooling, you're plenum is blown.

 

Multiple misfire codes and back firing threw the the throttle body during moderate/heavy throttle is another. How many miles do you have on it? Another forum i'm on had a pole when you did your plenum, Around 120-130K range was the highest.

 

First, replace the radiator. I just did mine a couple of months ago. Got an all aluminum including tanks. Took 1/2 hour to change.

Second, there is a plastic actuator that controls the blend door, the plastic breaks. If you go to heatertreater.net they have aluminum replacements (little pricy but worth it) and again it is about an 1/2 hour repair. The symptom is that you can get either completely cold or completely hot air, nothing in between.

Third, make sure there are no cracks or places for air to enter the system. Air gets into the heater core (even if it is new) since it is the highest point of the system and causes lukewarm air. You have to burp the system (do search, plenty of threads on that procedure).

 

99 should still be cable operated blend door. Think it changed to electronic in 00.

 

I believe 94 is the only year for the cable operated door, I think 95 was when they started using the electronic one.

But in a disagreement between myself and HeyYou, HeyYou usually wins!

 

My 96 has the cable operated blend door.

 

Told you!

 

nicely said, I plan on doing the radiator before the end of the month as winter is approaching and I need this truck for winter. I will check everything out and report back.

 

Just stumbled back acrossed this thread, I figured I'd update it. Since I bought the truck iv had it into the shop to have spark plugs in it because the old plugs were almost welded to the heads and I broke one of the distributor cap mounting bolts, the coil was bad so I replaced it since it was grounding out, the radiator ended up busting before I could replace it so it quickly climbed up the repair list. Got the radiator installed and roughly a week later the passenger side wheel fell off backing out of my driveway, somehow I snapped all 5 wheel studs off, had it towed and fixed again. After the wheel accident it was going great, I had nerf bars installed, the windows tinted, and a tonnoue cover installed, and the remote start I wanted installed. My exhaust ended up rusting out and falling off after the catalytic converter so I was trying to find what exhaust to go with when I lost reverse in my transmission. Took it into the shop and it needed rebuilt so the wife and I pulled the trigger and had the transmission and the transfer case rebuilt in one go around. Got it back and ordered my exhaust system for it, new catalytic converter and 02 sensors and a heart throb 3" cat back system. Litterally the day after I ordered the exhaust my waterpump started making noise because the shaft is going out. So I pulled the trigger to do everything at once. I'm doing the distributor, intake and plenum gaskets, water pump and fan clutch, timing chain, ect. So I think I can say this truck has been a pain in my butt since iv owned it lol. I still haven't had the differentials serviced but when I do I'm having it regeared to 4.10s with lockers and the posi lok front differential cable and a 3" suspension lift.

 

If you don`t mind me asking, what did it cost you to have the transmission and transfer case rebuilt ?. my truck is a 2000 with a 198000 miles on it, so its just a matter of time before I have to have my transmission and transfer case rebuilt.