I ran code tester (KOER) test and the tester grabbed a few codes.

13R (RPM at idle out of range/low)
25R (Knock not sensed during Dynamic Response test)
33R (EGR valve fault/ not closing properly)
44R (Thermactor air system fault)
52O (Power steering pressure switch open)
73O (Insufficient Throttle Position change during Dynamic Response test)

The truck has a bad studder that shakes the whole truck while driving. I'm not sure where to begin to fix it. Would the Thermactor system cause this? The egr valve is brand new and I don't know why the code 33r comes up...so I don't know.

Here is what I have replaced:
Head gasket
New egr valve
New EVP sensor
New TP sensor
New O2 sensor
Checked timing w/ a timing light
new plugs, wires, cap, rotor
Checked for air leaks -- none

anybody have any suggestions as to where to begin to fix this problem.

 

Hey Bebad96....

Check out my (last) post under "stumbling, pulled codes, now what ???"

It might be the answer you're looking for !!!!!

Good Luck,

Bob

 

Thanks for responing....did it fix the problem??

 

I should have read the post before respnding....lol...How did you test the egr valve without evp sensor? Did you just unplug it or remove it completely or what?

 

Well...

I took the sensor OFF then pressed the open end of the EGR valve, where the sensor mounts, against my belly to seal it off (I knew those Big Macs would pay off sometime ) then used a hand vacuum pump to check the EGR valve itself.
Kinda' like giving yourself a hickey !!!

Since the EGR valve had ZERO vac loss (against my belly), I determined the leak was coming from the sensor or the seal on the sensor.

If you don't have a hand vacuum pump, take your rig to an automotive shop and ask (or bribe with a sixer or other suitable item) one of the mechanics to test your EGR valve to see how fast it bleeds off vacuum.


Good Luck !!
Bob

 

Thanks Bob, I think I might pick up a hand vacuum pump tomorrow...I hope this fixes my problem...I'll just save the sixer for myself while I'm testing tomorrow..lol...thanks again.

 

You Betcha'

But you gotta' tell ALL of us if that was/is your problem and if its fixed now, O.K. ???

Bob

 

Well, it didn't fix my problem, completely. It did help it alot. I found a partial leak at the evp sensor, so I slapped some sealer on and it sealed it up great. It still has a studder but, not as bad. I wonder if the computer has to learn how to run with it sealed up...

Also, when I checked the egr vacuum hose for suction, it didn't have any at all when the engine was running...so what would cause that, the egr soleniod or something in the thermactor system?

 

The thermactor air is most likely not part of the problem as it is not directly connected to the intake manifold Only to the exhaust. Sounds like your problem is on the intake side. Have you checked the egr solenoid to see if it is working.?

 

When I hooked the hand vacuum pump to the green vacuum hose, the gauge was reading 0 when the engine was running. So, that's why I think that the egr solenoid is not working. This problem has really got me stumped. Keep the suggestions coming...

 

Dang........

I thought we had it.

Well let's see.......
I don't think you should be getting vacuum from the green hose while the engine is idling. It should kick in somewhere around 1000-1500 rpms. At least mine does.
Do you get vacuum from the green hose then ?????
If not, check the two solenoids (directions in Haynes manual) that control the vacuum mess.

Next.....
I re-read your post and you had an error code that was puzzling.

You had an error code of a not fully closing EGR valve.
When you replaced your EGR valve did you get the correct one ???
By that I mean when I replaced mine I had to give the autoparts store (Napa) my VIN number to get the correct EGR valve that matches with the emissions calibration number.
Sounds exotic, but I guess even though they may look the same, EGR valves are NOT interchangable !!!

Now my bad news......

I replaced the TPS tonight with an OEM Motorcraft one.
My truck seemed to run fine up and down the road till I got home, put it in park and slowly increased the throttle to 1500 rpms and the stumble reared its ugly head again.

Also, ANYONE have a clue as to why the check valve in my transmission (E4OD) starts buzzing at about 1200-1500 rpms.
Could this be directly related to the "stumbling" problem ???

Sorry---Didn't mean to hijack your post. I'm DESPERATE to get my truck running correctly too.

Albeit like you, my stumble is not as bad as it was before, but it's still there.
I know that these trucks ran perfect when they were new, and driven off the lot, and I'm bound and determined to get mine back that way.

Anyone out there have "THE ANSWER" for us ???---lurkers, casual readers, Ford Technicians ???

Bob

 

I didn't get any vacuum period....I hope that the autoparts store gave me the right egr valve, $80 dollars later!! The studder was there even with the old egr valve, so I think I got the right one. I'm going to replace the knock sensor tomorrow and hope that it fixes the problem. I'm at a loss for ideas....Anybody with any suggestions please, don't be afraid to say something.

 

"When I hooked the hand vacuum pump to the green vacuum hose, the gauge was reading 0 when the engine was running. So, that's why I think that the egr solenoid is not working. This problem has really got me stumped. Keep the suggestions coming..."

Disconnect the connector from the vacuum solenoid and check it with a meter, or connect an external 12 volt source and see it it clicks. Hook up an external vacuum to the red tube and apply voltage to the solenoid vacuum should be vented if its working.

 

i have an '87 4wd 4spd, and after replacing a cracked head, i had a similar problem, and the same codes. about an hour ago, i pulled off the a.i.r. thermactor hose (the one that goes to that really expensive, poorly designed rail in the head.), as well as the line from the exhaust to the e.g.r. valve. i started it up with both lines off. the idle was kind of spotty, but the hesitation and bad stumble were gone. and, of course, it was kind of loud. i then put the e.g.r. line back on. i retimed it, because there was still some lugging, and even that went away. the truck now runs like it did before the cracked head incident, which is to say, with an intermittent miss at idle, which i ay or may not actually try to fix. later, i might attach the a.i.r. hose and see what happens, but now i'm just glad to have my truck driveable after more than a month of struggling with it. my advice is, keep messing with the a.i.r./thermactor, and e.g.r. systems. i was seriously considering putting a carb on this thing.

 

I will try disconnecting those lines tomorrow. My truck had a miss at idle before it blew a head gasket. But, I could live with it. One thing I can't live with is this studder...man is it annoying. I was thinking of putting a carb on it too...but I like the fuel injection, call me crazy...I just want to fix this stupid studder.