ok, 97 F150 4.6L V8 4x4

#1.
i posted a few weeks ago about a bucking/jolting/jumping at around 40 or so mph....i have researched and discovered it may be something going on with the torque converter...about 40 or so mph, in OD, with slight acceleration, sometimes it bucks; but if i lay a heavy foot on the gas, it masks the bucking and downshifts to higher rpms and then shifts back into OD...does the TC need replaced or something going on with the TCC solenoid??

#2.
still have the P0401 EGR insufficient flow detected code...when the truck is running, i reach under the hood and i pull the vacuum line to the EGR valve and i can hear it "plop" and when i reconnect it, i hear it "plop" again, closing and opening i guess is what its doing...im not sure if its the valve needed replaced or not...lil confused on what to do about both probs...

this forums has helped me with just about every problem ive ran into, such as an IAC, A/C, 4x4, PCM probs, and more...see if we can get anywhere with these lil buggers

 

just popping up to the top, need some help here

 

any advice any1??

 

As far as the tranny problem.. My 97 Lariat had that problem.. Sorta.. This is probably not even going to relate but no one else has posted anything so its worth a shot. I guess? LoL. When I would pull off from a redlight it would have a bucking feeling right after it shifted. BUT mine was only doing this when I would lay into it hard. I went and decided to attemp a cheap fix because due to a short money supply at the time. I simply went to the parts store and read the back of the bottles around transmissing stabilizer area. When I found one that somewhat matched my problem I bought it, followed the instructions on how to use it. I drove around for a little while and noticed it was running a little easier. It seemed that the more I drove around after that the more the stuff worked its magic. Now it runs and shifts decent as a truck should so to speak. Maybe this was some help.. Maybe not. LOL.. It was worth a shot..

 

The tranny problrm could either be torque converter clutch chatter ( that a good fluid flush ususally fixes) or an ignition miss that only shows up when the load is heavy (such as around 40mph in OD and the converter is locked.

Is there vacuum to the EGR valve at idle?

 

tranny fluid and filter changed just the other day, as long as the fuel filter and TPS...yes there is vacuum to the EGR valve at idle...ordered TB gasket today will be in tomorrow and will clean out ports while i have a p0401 code that i can seem to get rid of...but i was thinkin its prolly gonna be something with the TC...only seems to buck just a couple times while in OD...doesnt do it too much, but it does do it often...

PS-when my truck was acting up before the TPS was replaced, OD would engage about 20-25mph and would buck then too...but it never drops in OD at 20 anymore...so its something with overdrive or sumthing i believe, i dont think its very severe, but wanna try to get this fixed cheaply as fast as i can lol

 

While the EGR code smells of carboned up lines restricting flow, the accumulation can also make these valves act erractically. The crud can block the valve from closing fully.

However your "bucking/jolting/jumping" doesn't sound directly related. Keep in mind that a studdering FI motor, can give that feel & also accelerate wear on a tranny by passing the unintended & excess power fluctuations thru it.

There also has been a steady stream of comments about tranny issues popping up after changing & flushing "tranny fluid". Resolve the code & see if it still bucks.

 

with the engine running at an idle, open the egr valve with vacuum. Engine should die down and or run rough. If not egr port is probably plugged. I would suspect an engine missfire under load for the bucking, I have quite a few that will miss under light load in overdrive and converter clutch locked up.

 

If you're trying to fix it on the cheap, fix the easy one first and se what happens. Clean the EGR ports and run from there. I agree with ranger, sounds like you have a misfire, but you're the one driving it. If it feels like a bucking tranny, maybe it is.

 

well, the bucking only happens when it drops into OD, if i have OD off by the shift handle, there is no bucking...also i read somewhere else about the TC or TCC solenoid diagnosis is to wait for it to kick into OD and lightly press the brake and the engine should rev up...tried it and the engine does revv up...not sure whats bad or what needs work on exactly...

if i stomp my foot on the gas it does buck erratically, but i think it is my EGR prob that has just gotten worse...only does it if i romp down on it tho...i wish trucks were alot easier to work on nowadays...

btw, spark plugs and wires only have about 25k miles or so on them, so highly doubtful thats the prob, but ya never know...i will check tomorrow when i take the TB off and clean EGR ports...and also i have had the truck running and individually unplugged 1 injector at a time, every single one resulted in an rpm drop, so that leads me to believe thats not my problem

and idk if it could be a coil about to give out, or either if theyre good or bad...since it only hesitates/bucks when i put the pedal to the medal...also dont forget that i think my OD is a diff prob than the hesitation im having

 

I had a 96 model that did similar things...@ about 90K I got the torque converter replaced because when she shifted into od it had a disernable shudder if you stayed at low rpms (between 40-50mph). Felt like a rough idle or something. But I tryed changing the fluid and filter, it didn't help. I remember when I took it to the shop the guy told me it happened all the time to fords. I hadn't owned the truck long and I suspect the previous owner hadn't changed the fluid properly. I stuck to ford's recomendation @ 30K and haven't had any problems since. On the exhaust front, I had true duels put on that truck (no cats, just 2-30" glass packs) I used to get the insuf EGR flow code constantly. Took it to a shop and had the Exhaust gas sensor thingy replaced. Fixed it for about a year, then it threw the code again. Then I took the check engine light bulb out of the dash. No more problems since. Maybe this will help

 

well i was anxious to check to see if i had a misfire, since no code has been thrown yet about a misfire, but i think i found my hesitation prob when i stomp down on the gas...first plug wire i pulled, came out very easily...i shined a light down inside, there was mud caked in the plug hole, and not much of the plug itself showing, so i went to peckin and chiselin with a screwdriver, and took a drinkin straw, lol dirt all in my eyes, since i dont have an air compressor handy, and blew all the dirt out...took a while but seemed to help my hesitation...havent had a chance to see if it still bucks in OD yet tho, ill post results tomorrow after i go to work...also have a TB gasket ready in the morning so ill be gettin rid of that P0401 code i hope lol

 

well, removed the TB today, and boy were those EGR ports clogged...there was nothing getting thru those lines...i could hardly tell they were actual ports lol...had carbon buildup stickin out of the hole...and believe it or not, for sum reason, before i did this job, my gas pedal has always had tension on it when pushing the accelerator down...its smooth and feather light to push the pedal now, makes me feel alot better about the engine itself now...

but still having slight hesitation, which i havent check all the other plugs yet, and still dont think i have that one where i saw all the caked mud as clean as it needs to be yet...hopefully that P0401 code doesnt pop back up

BTW, the vacuum lines, they were put on backwards for sum reason..the green line was hooked up to the EVAC and a white line hooked to the EGR valve...the green has a pulsating vacuum and showed to be hooked up to the EGR valve, the white one has a constant vacuum...but where does this white one go, the EVAC?

According to the vacuum diagram under the hood, theres a red line going to the fuel pressure regulator..good...the green to the EGR valve...good....then the white one goes sumwhere...reason idk where the white one goes, is cuz the diagram shows the vacuum line to the EVAP is a brownish color??

 

ok, found a diagram sayin that a tan one runs to the EVAC, and its a dark whitish color, believing it to be tan...think i have it set up right now lol...also, before i cleaned out EGR ports, you can touch and hold the EGR pipe with your bare hand...now you cant lay a finger on it for more than 1/4 of a second before you burn your finger off lol

 

I know this thread is a little old but my 97 f150 4x4 with the 4.6L was throwing the P0401 EGR insufficient flow detected code. That was a month and a half ago and i have now replaced the vacuum regulator, egr tube, egr valve, IAC, and dpfe sensor with all autozone parts (except the egr tube was from ford). the code came up again today and the engine will go all the way down to about 250 rpms when stopping and sometimes all the way to zero (dies) (especially when turning and braking, also it only does it when it is at operating temperature.) Do you think I should just buy a dpfe and a iac from ford and see if that fixes it or just have ford diagnose it.

Right after i posted that i went outside got the old IAC and Dpfe, sprayed some wd40 on them drove 17 miles down roads with stop signs and it did awesome. I guess I'll see in the next few days if the dpfe is still good. I'm never buying Duralast again and only buying Motorcraft.