2000 5.4 auto trans. 326K showing and supposedly rebuilt at 180K

Have the p0174 code and under load, the exhaust sounds flat and lifeless kind of like badly retarded timing will do. Pulling the trailer it seems ok on level road, but when it kicks out of OD and the rpm goes up is when it sounds different, looses a good bit of power and even develops a vibration like one or more cylinders is missing

I have tested the MAF sensor and it checks fine. I recently changed the plugs and cleaned and re lubed the COP springs that contact the spark plugs with dielectric grease. It had developed a bad miss before the tuneup and found the plugs hadn't been changed in who knows when and were badly burned. Someone also used regular grease on the COP springs and it was caked and dried very badly.

I just checked the PCV hose for leaks/kinks and it has tons of vacuum, however the PVC valve is making a sound as though something is vibrating inside it, so pulled it out and the little valve is very loose and floating around in there. Put it back in and now the truck doesn't want to idle and dies.

Never heard of a PCV valve causing that. Any of you experienced that?

I live about 20 miles from an auto parts store, but will run in later and pick up a new valve. Anything else to look for I should maybe pick up as well?

Sorry for posting a novel, but wanted to give all the info I could

 

Forgot to mention whoever had the dual exhaust put on had the Cat removed. No, I'm not in California

 

The PCV valve should be loose and rattle when you take it out and shake but not when engine running. Sounds like you disturbed a vacuum leak when you removed and reinstalled it. Those hoses get soft and crack in hard to identify places over time.

 

Thanks for the reply.

I checked all the vacuum lines and found no leak. The PCV valve was totally fried as the check valve inside was loose and rattling around like mad. I installed a new one and the engine no longer dies when plugging/unplugging the PCV valve. It seems to run a bit better, but still has no snap like it should.

 

Think I found the problem. Picked up a cheap mechanics stethoscope at Harbor freight today and modified it with some rubber tubing in place of the steel rod to listen for vacuum leaks I could hear air around three or four of the seals between the plenum and the lower intake. Didn't have any carb cleaner to spray in there to verify though. How much of a PITA are these to change the O rings in?

 

It's not too bad it's just hard to get to the back side if the upper intake otherwise it's really easy

 

^^ Just a few of the bolts are tough to reach. The intake comes off pretty easy. I would go for it...