2001 4.6 65k

It idles fine and cruises fine, for the most part. It's only under torque that I feel it. It's the same stumble I felt when I had an EGR sensor code. Replaced it and all was fine. So I unplugged the new sensor, which is only two months old and it ran fine for several miles then the ses light came on of course and the stumble returned. I changed that sensor again under warranty and cleared the ses but didn't fix the problem. Last year when I had this problem I thought it was the tranny slipping so I did a drain and filter which did not fix it. that was before knowing it was the egr sensor.
So I have an engine problem and no ses light, so far, to give me any clue.

thoughts?

 

Did you ever read the codes before clearing them? What were the exact codes?

Have you tried cleaning the throttle body, paying attention to the EGR ports? The 4.6 is known for clogging. How are all the vacuum lines in the EGR system? Have you suck tested the EGR valve itself?

 

Thanks GLC. I didn't have any codes when the skipping started. Well, the ses wasn't on anyway. It was the same feeling as the last time it was in fact the egr sensor. When I unplugged the egr sensor that's what made the ses light come on as I expected it would. But it ran much better for several miles unplugged then came started doing it again. Coincidence?
I have not removed the egr but if I suck on the line I can hear the valve open/close.
Because it wasn't the sensor, and the ses hasn't come on yet, I'm thinking a COP or injector? I may just have to wait for the ses to come on to give me some guidance.

 

you didn't answer glc's question of did you clean the carbon out of the EGR ports of the throttle body?

 

No actually i did not. other than spraying carb/choke cleaner into it. ill give that a try as well.
another question, should the engine die when I pull the air intake off the tb?
on my BMW that's usually a sign of a MAF problem.

 

It shouldn't die - but it will run pretty bad.

Suck test the EGR valve with it RUNNING - it should stumble and probably die.

 

well it does die. so should i look further toward a MAF? I sprayed with with electronic cleaner with no difference.

the suck test is ok. it stumbles badly. if i could take a deeper breath it would die.

cleaned out the pvc valve. it was making a very noticable rattle sound. there is strong suction there also.

 

A bad MAF should throw a code.

 

I kind of have a similar problem. My 02 expy has a 4.6 in it and it kicks going down the interstate. Drove to Indianapolis from Nashville last weekend and it kicked/stumbled about 7-8 times. Took it to the local shop and he threw some fuel cleaner in it and it did nothing(surprise surpise). Then when i got back to Nashville (by the way it kicked about 10-12times on the way back) took it to my local shop and he drove it about 30 miles before it kicked again and when it did finally kick he had it hooked up to the reader and it threw a cam shaft sensor code? they changed the cam shaft sensor and now it kicks/stumbles even worse! the engine light has yet to come on....not sure why....at first it only kicked/stumbled at 65-75 mph, now after they changed the cam shaft sensor it kicks/stumbles at any speed......any suggestions? thanks..

 

OK heres my story, 2004 screw 5.4 120k, had a problem with rough idle aboi found those all seem to be lean codes ut 15000 ago at that time changed plugs (broke 4) nice. got a little better disassembeled throttle body and cleaned thouroughly (was quite dirty) got a little better have changed ; camshaft position sensors, fuel filter, tps (tps fixed rough idle) had a torn vct boot that was leaking oil changed that. heres my current problem, truck idles smooth accelerates smooth except when under load then it stumbles as it reaches about 55 or 60 mph, by holding it in this range got it to throw some codes 0171, 0113, 2197 cleaned the maf seemed to get a little better. if i stomp on it it gets up just fine only stumbles under smooth acceleration. found those to be lean codes could it be a bad maf? dont think its a vac leak as it idles well, dont detect a miss(i think) possibly cops? any ideas would be appreciated, also ran seafoam through it etc.

 

You last couple of guys should start your own threads.

It can get confusing when you post your problems in someone elses thread. Even if it is a similar (or seems to be) issue, it can keep the confusion down and get you help faster.


Jdflow, I would also recommend removing and cleaning the TB and egr ports. Clean the IAC with wd40 while you have the TB off.

Also, when was the last fuel filter change? COP's or coil packs (whichever you have) could also be causing a misfire? Might be worth a plug change and inspect the old ones. It's all good maintenance either way but helps narrow down the hesitation issue