I have been slowly working on this truck since I bought it two years ago with 190,000 miles on it, now sitting at just under 238,000. Last year I abused the hell out of it while working for a construction company. Since then it has had a rough idle, stalling issues, excessive fuel consumption, as well as some shifting issues during acceleration and a few others. As I researched these problems, I kept finding the best information on this forum. It seemed that for every problem I had, someone had brought it up and fixed the issue. But now I a bit stumped.
So far I have:
-Flushed the engine oil (Seafoam & Oil/Filter change three times)
-Flushed & changed transmission fluid/filter
-Cleaned fuel system (Seafoam through vacuum & other injector cleaner fuel treatment)
-Changed distributor
-Regular (8,000-10,000 miles) plug (Champion), air filter, and cap & rotor replacements
-Replaced starter (damaged from too many stalls/hard starts)
-Repaired and replaced every damaged & dryrotted vacuum hose/cap I could find
-Replaced PCV
-Replaced IAC & cleaned port (And new IAC is functioning correctly as apparently they have a bad track record for new ones failing)
-Replaced Fuel Pump (my gauge was on the fritz and finally irreparably failed, and so had to replace the entire package)
-Solvent soaked and scrubbed throttle body
-Replaced fuel filter
There may be one or two things that I am forgetting that I have done engine wise, it has been a busy week. Every one of these repairs has resulted in better engine performance, but I am still getting a rough idle, the stalling issue has disappeared completely. I was hoping that there may be a suggestion or two that might help out. I have a week to get the truck ready to drive back to Oregon from here in Orlando with my wife and daughter, not a good time to break down for something simple.

 

Check the PCV hose again, maybe it has a crack.

 

That was what actually made me change the PCV today. I was cleaning grease off of the recess between intake and valve cover and saw the PCV hose was dry-rotted and split about an inch back from the intake, so I replaced them both. Beyond the vacuum leak there was an extreme amount of grease/carbon buildup in both, hose was almost completely clogged and pulling in through the leak only.

 

What about the rubber grommet?

http://www.autozone.com/autozone/par...2885_322634_0_

 

Have you checked OBD for codes?

 

The grommet is new, and the only code is 33, A/C clutch relay circuit, as I have removed the relay.

 

Have you done the plug wires also?

O2 sensor replaced? and cleaned up the EGR valve if you're has it.

Importantly does it ever idle smooth, right at start up or after it's warmed up?

 

I replaced the O2 sensor today as well as my rusted-through muffler, smoothed the idle quite a bit. It seems to stall right at startup now unless I hold the gas for a few seconds, but I will drive it a few more days to see if the ECM learns the new sensor & adjusts. And what would be the best way to go about cleaning the EGR? The valve itself seems a bit rusted, I would like to replace it but that may be out of the question financially right now. . .

 

Pull it out and flush it with carb cleaner, won't be perfect but should work.

TPS could be an issue and it's easy enough to test.

 

Okay so today I pulled the EGR to check it and it was pretty bad, decided to bite the bullet and just replace it. TPS was good. I figured while the engine was completely cool I would replace the valve cover gaskets that I have been forgetting to take care of for a while. Only three bolts on the left cover were tight and one on the right. Every other bolt was able to be removed by hand, and had quite a bit of caked oil under them, so I would assume they had been that loose for quite some time. I am pretty sure I found where my half-quart of oil every 300 miles was escaping. There was quite a bit of buildup inside the covers, was wondering if this was typical for these engines around 238k miles?



But after replacing the EGR my engine is running smother than it ever has. . . I really do appreciate the help guys.