It does have the COPs. I see no evidence of it ever having coil packs. Is there a test for the EGR? Is the EGR valve on the 4.6 cleanable or is it some throw away design? Is it possible the EGR fault is due to the lack of combustion from the failing 4 cylinders? All indications to me are those 4 cylinders are not firing but is it due to lack of fuel, lack of fire or some other condition? Have AM appointment get started back on this later today. I really appreciate all you guys help and advice. This elderly couple are just old friends who pour out their lives helping children until they have nothing left. He is a medically retired vet and she is a girl scout leader. I'm a medically retired vet as well, but 10 years younger and not on SS, but just trying to pay a little back to such wonderful people. I just volunteer to try and do as much light mechanical work as possible for them.

 

 

Thank you for the video test.

 

During the quick test I could feel vacuum but reveled no change in engine rpms or idle while covering the nipple.

 

That usually means restricted passages or stuck closed EGR-valve. It may be possible to clean it, you'll have to take it out and see if it's possible.

 

Lighten up a bit, no one was attacking anyone. All he was doing was conversing to try and get at the root of the problem with the vehicle. This is the internet where thick skin is pretty much mandatory. Now if he said something like, "don't listen to this dope" then I'd see your point.

 

OK I removed the EGR Valve and checked it. I could move it easy. I cleaned and lubed it and it moves very easily now. I'm confident the EGR valve is not the cause of the PO401. I reinstalled it and ran the test again and their is still no change in engine idle or rpms. I checked the electrical connector with a test light and it did light. Could a engine vacuum leak cause the PO401? If there was an internal leak would it cause the PO401? Any idea what I should try next in this effort to correct the main issue of bank 2 being to lean and all four cylinders at PO305 through PO308. Thanks again.

 

Also, check the common wire to #5,6,7, and 8 COP, harness side w/KOEO, for battery voltage. (I have trouble interpreting my test light's brightness.)

 

I don't think so. But the misfires could be causing the Bank#2 lean condition as the O2 from those misfires goes right by the O2 sensor on that bank.


If you have a scan tool you might want to look at the freeze frame data to see which DTC came first.

 

No change in RPM would indicate a ruptured EGR diaphragm or a stuck EGR pintle and/or plugged EGR passages in the intake manifold/throttle body. Pull the throttle body and check the passage way.


Could be a bad DPFE. What voltage readings did you get as described by Scanner Danner?

 

If the EGR pintle moves fully up and down when vacuum is applied could the diaphragm still be ruptured? I have a ACTRON super autoscanner but I am unsure if it reads the DPFE. What is a DPFE and how is it identified?

 

If the pintle moves up and stays up with vacuum, and the vacuum doesn't deteriorate, I would say the diaphragm is good. And if the pintle closes when you remove vacuum, the pintle is not stuck.
But if there is no change in RPMs when at idle as the pintle opens, sounds like a plugged passage, as the idle should stumble or stall as the open EGR dumps exhaust into the intake at idle.


The DPFE is an abbreviation for Delta Pressure Feedback EGR. The two hoses from the DPFE connect to the EGR pipe. Between those two connection within the EGR pipe is a fixed orifice, so the DPFE sensor compares the pressure on each side of the orifice to determine EGR flow.

 

Thanks for the tip. I pulled the throttle body and sure enough the EGR passages were plugged tight. I cleaned out the passages and cleaned up the throttle body and the EGR system now works properly. I cleared the codes with the scanner and drove the vehicle and the EGR code did not reset and neither did misfire of cylinders 5 or 6 but the Bank 2 lean code and misfire at cylinders 7 and 8 reset. I have removed the cop and spark plugs from 7 and 8. The coils test good and the plugs look good and are gapped properly and only have 5k miles since put in new. Any idea where might be the best place to start resolving the cylinder 7 and 8 misfire along with the bank 2 lean fault?

 

Just as an aside, I had an old timmy ignition guru tell me back in the 1950's that ohming out a coil can tell if its bad, BUT, it can't tell you if its good! In other words, the very small amount of current that the ohm meter puts through the coil is very different than 6 or 7 amps of current that goes through it when its running.


So your coil is not "bad", but we need to find out if its "good". What I'd do is take the coil from #7 and swap it with #5 and the boot from #7 and swap it with #6 and then drive it. See if the misfire from #7 moves to 5 or 6. If it does, you know what is the culprit. If it doesn't move, we'll have to dig a little deeper.

 

I understand. I'll give your suggestion a try.