You're exactly right - ignoring the codes leaves nothing but wild guesses.

I've pulled up a bunch of info on sensor voltages/impedance/whatnot - I'm going to test some of the 'usual suspects' and see where that takes me. Past that, the only real culprit that I can logically look toward is the O2 sensor.

Outside the computer world, the cap/rotor seem like suspect items.

 

One other little thing I've noticed... I ran seafoam through this thing over the past couple of days, and after doing the intake yesterday, it was blowing some black junk out the tailpipe.

Looking at the EGR valve, some of it was blowing past the compression fitting for the exhaust inlet tube. This sounds silly, but should I have put some thread sealer on that fitting? There is none on there since replacing the valve - could that be allowing an exhaust leak that would have some sort of negative effect?

 

Thread sealer won't last on that fitting, it's supposed to be self sealing. Tighten it up some more. I wouldn't think it would make a big difference in running condition. I haven't used Seafoam, but the carbon deposits have to go somewhere.

 

I wondered about that - it's pretty hot in there.

I'll try to crank it down a bit more. Over the course of the weekend, I hope to check voltages on some of the other sensors, and pick up a fuel pressure guage to see if by chance the fuel pressure regulator is messing with me.

 

One other wild guess here - any possibility that it could be the transmission? It should bring up a code, but I don't know when the fluid was last changed if ever.

I'm not a mechanic for sure, and transmissions scare me to death. Do you think that old fluid could cause any of the stutter and chugging? I have no idea what I'm talking about, but it seems like logically, if the tranny was slipping it would be worse at higher rpm and better at low rpm? Just the opposite of what my truck is doing...

 

Transmissions slip worse when taking off from a stop. There is more force and heat involved. When you are already moving it slips less because it doesn't take as much effort to keep a moving object moving. I don't think the tranny is your problem but a fluid and filter change won't hurt it either.

 

just buy a chevy. fords have bad gas millage and are always found on the road dead

 

To rule out the EGR valve failure to close as the reason for the poor Idle, cut a piece of metal (or even cardboard temporarily but will burn through) that you can slide between the the EGR and the block and tighten the EGR back down. If the idle improves, the EGR is in fact, not seating completely & the code correct.

 

I would have thought a 3 C-note+ Partsfest would have a new cap & rotor already under your belt. New plugs & wires w/o cap & rotor? You don't strike me as the type that does anything half way. Point being, your Ignition system is only as good as its weakest link allows. A cap/rotor prob would tend to blend into a blur of increased RPM, seeming less prominent than at an idle. .

 

Yeah... I'm not sure how I screwed the cap/rotor up, but I'll be replacing those soon. And I sure hope it helps!

On the EGR idea, I tried that tonight - I already had an aluminum block-off plate milled just in case this thing went too far. I put that on between the valve and intake and bolted it back up - absolutely no change! I'm certain now that something else is causing the EGR code to pop up.

The guy at the parts store seems to think the O2 sensor is to blame for a lot of these things. He even admits that a lot of people buy parts after parts until finally they buy an O2 sensor and he doesn't see them for awhile.

Something's gotta give, or I'm gonna buy a cliff and drive it off the edge!