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My very own hesitation/bucking thread

Hey all - wanted to chime in here - my 2000 CSVT has a buck that occurs in 3rd gear between 2K and 3K rpm, just like t.lynn.c (this is the 1st time I've heard someone describe it as exactly as I'm experiencing). Here's my story - I replaced my fuel pump with the updated Ford PFS289 pump as a precaution - no symptoms before the fuel pump install, that I can recall. Around the time I put in the replacement pump (this is the one that requires cutting the ring in the bottom of the tank - all went well during the install), I noticed the slight hesitation in 3rd gear between 2K - 3K rpm. Seemed to be getting a bit worse (or perhaps I was getting more hypersensitive to it). Pump lasted about 10K miles and quit working on me one day in an intersection. I then installed a 2nd Motorcraft pump, which is currently in the car. Still has the buck/hesitation in 3rd gear. Stone cold, the car runs fine - smooth acceleration. Shortly thereafter, the buck starts - it's more severe some days than others. I'm so frustrated with this, also wondering whether this pump is going to fail again. I've tried pretty much everything else - new Motorcraft wires and OEM plugs, cleaned MAF, switched fuel pump relays, checked fuel pump driver module for functionality, checked fuel pump wiring, etc. Engine coolant temp sensor is fairly new. I'm seriously thinking of getting a used fuel tank that still has the old style pump in it and installing that just to see if the problem goes away. I did not install the flapper valve mod when I replaced the pump, since I did the pump install by cutting the floor rather than removing the tank - wouldn't think that should make a difference? Anyway - just food for thought - everyone that's having this problem - do you know if you have the updated Motorcraft pump or the original style pump? I should also say - I have the P0420 code for precats so the check-engine light is on for that, but every time I run a scan on it, it's the only code I'm getting, so I'm never getting actual misfire codes despite the buck/hesitation I'm experiencing. So the P0420 does complicate my situation a bit, as it could be maybe causing some driveability problems, but I thought others have driven around with this code and MIL eliminators for many miles with no driveability problems.
 
I had a hesitation/bucking issue for awhile too. just got worse until it finally sputtered out and died on me tonight.

After a couple 20 minutes of gas station troubleshooting, I found a loose connector on top of my fuel pump. the tabs were broken off of the sides. plugged it back in, used some wire to secure it, and she was good to go.

no more mid rpm stuttering.

maybe that's too easy.
 
James1767, thats sounds exactly like mine stone cold runs great then as she warms up bring on the bucking. I don't know what style pump I have due to I've not had the car long and I've basically been trying to decide where to start to fix the problem. And I still don't know, I've tried unplugging different things and driving it and it's always still there. I have ran a scanner on it and I get no codes also.
 
Having said all that stuff in my last paragraph, now for the past few days the car seems to be running fine. So my 2K-3K buck is intermittent now. But toward the end of the previous PSF289 fuel pump's life, it was constant, so I keep thinking it's a fuel pump issue, like the pump is being overworked or something. I need to start keeping a log of when it occurs - like a particular level of fuel in the tank, a particular brand of gasoline used, etc. I'll keep updating this!
 
jborge said:
Well I might as well keep this famous thread running. I have read it all at least twice.

Here is my problem:
Idles fine under no load. With Idle and load I get a slight buck/surge once in a while (i.e in drive with break on, or at a stop light).
When accelerating Misfiring jerking/bucking occurs in the 2300-2500 range. Once in a while I get a blinking cel for bad misfires.
I am only pulling missfire codes,nothing else and it is moving around to different cylinders, P0303,4,5,6 and one P0300. I am not pulling any other codes.

Coilpack, 2 sets of motocraft plugs and new wires cleaned MAF and IAC. Sprayed carbcleaner around engine for leaks and checked hoses.

So bucks at idle underload and acceleration around the 2500RPM (i.e. acceleration onto highway).

I am going to look at the EGR next. Any feedback would be good even though it is ,most likely somewhere in this thread.
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I am just updating my status (as I hate it when people never never follow up with their outcome), new wires and plugs and now everything is running good again.
So I threw new wires and plugs in the garbage. That is what you get when you don't do your plugs and wires at a the same time. I was chasing my tail there for a while.
 
sorry that you had to throw new parts out. As always its recommended to change the plugs and wires at the same time since carbon tracking is common in these cars.


also here is something new that some might try. I was getting what felt like a miss, randomly, at high rpm and load and wot. All ofther times it wasn't to noticable. I swapped the coil pack but what i noticed was the part of the ground strap and the coil body where it contacted was rather rusty looking. The used coil I installed was cleaner and I turned the ground strap eye-let over. no more miss in the high rpm/load/wot condition.

Either way it can't hurt to make sure the ground is good.
 
Are any of you guys changing your EGR valve and/or DPFE Sensors?
When the car is looking for exhaust gas (to slow the combustion process), and none flows through, it will cause the car to run rough as well.
EGR will flow through upon light throttle, never at idle, and never at full throttle.
Apparently these cars are known to eat through DPFE sensors? I have to change mine this weekend.
 
egr valves realy fail. yes the dpfe sensor do often go but thats because they are orginally metal and corrode from the inside. the new ones are plastic. otherwise not to many issues. yes a open egr valve at idle will cause a rough idle.
 
Has anyone else had any problems with the 9mm ford racing wires? I had a hesitation at certain rpms and changed from those to regular wires and it fixed the issue 100%. Had the same problem with the 95 se a while back same scenario. So that's 2 bad sets of ford wires for 2 different tours.
 
I personally had the same issue with the Ford Racing wires, as well as several people at NECO. They are definitely hit-and-miss; some have had no issues at all.
 
My car bucks and jerks,i found it to be that my wire harness is all cracked and falling to pieces everywhere and i mean everywhere lol.... after i taped a few things up that were touching it went away but comes back every now and then.....i also seem to have an issue when i get below quarter tank it does this to so it could be both or 1 or the other for me probably with my luck its both.
 
svt1480 said:
did anyone ever end up changing the (camshaft position sensor)??? man cause i got the same problem too!! an i got the 3L but i got the 2.5L everything else. one day i got a po340 code an i went home an unplugged the sensor an turned the car on, the code was gone. then drove it an the buck was gone.......
Click to expand...
yes! this.

My car idles badly and run the same. But when the sensor was disconnected, it all went away!

What does this mean??
 
wow, im having the same problem but mine is egr related, i tested my EGR(vacuum when car is running) and it tested good, i also checked my tubes and they look good, i'm leaning towards the DPFE but i was curious if anyone knows how to test it without a scan tool. I have the old style sensor, but i cant tell if its bad, wires appear good. The car only has 107k miles(2000 csvt) but my symptoms are exactly how he described but no CEL for a misfire and I'm getting an EGR code(s). I'd hate to spend so much money like this guy did and thank you for the update, its rare when people do that! I checked my plugs and they look like they were recently replaced but i'm not the old owner so i don't know what he did before you got rid of it.
 
Hello all -

It's been several months since my last post on this thread, did not want to leave my story open-ended. My car has been running fine with absolutely no hesitation now since approximately early spring/late winter. I cannot really explain it. The only change I made around the time the hesitation smoothed out and disappeared was this: my car has the fuel filler flapper valve problem - when you fill the gas tank, the fuel station fill pump overflows gasoline up out of the filler and embarrassingly down onto the ground. I now NEVER fill the tank to the point that the fuel station pump shuts off - I eyeball the gallons and stop when I know it's near full. Car runs smooth and strong. Maybe overfilling the fuel tank allows raw fuel into the EVAP system, and that could affect the operation of the EVAP system and somehow result in the slight buck/hesitation I had? Car had 31K on it when I bought it, now has about 115K, runs as strong as it did the day I got it. Still wish I had a more definitive answer on this...!
 
hum....can't believe that I sat here and read though the entire post.
So, here's my story, over a month ago, out of the blue, while driving on the Interstate, the car started bucking/jerking/ like it was jumping gears. (it's a automatic) First thing I thought was lost the tranny. Well, that wasn't it. Did lots of reading, I first cleaned the MAS. Absolutely no help . Then I remembered that the day this started, I had just Filled the tank, at a different station.
So, I'm thinking bad gas. I drove as best I could trying to get close to empty. Then I filled it up and added carb/injector treatment. It appeared that the problem was fixed. Jumping for joy. So down to half tank, and , you guessed it. the jerking/bucking is back..So fill it and and treatment. Driving fine....and then it started all over again!!! Dang. This time the CEL came on. It never had before. So, James, I think there definitely is something about the level of gas in the tank. (Also, I'm reminded of what previous owner told me the day I purchased. He said that the gas gauge did not work properly...Said, once it read 1/4 tank, and he ran out of gas. Was talking about how embarassing that way. But after reading up on fuel pumps and contours, I doubt he really was out.

Also, it was mentioned towards the end of this thread, that other fixed this problem by installing a new TRS (transmission range sensor) also known as a Neutral Safety Switch, and if believe there's another name for it,.....starts with a M??????
As for me, come payday, I'm going to try a new TRS and see.
Just thought I'd throw my thoughts at the problem... Is it possible, that there is more than just one issue going on here?
 
Mine still shakes a little while slow acceleration ,i need to install my polyfilled front tranny mount that i did and buy a new roll resistor,both mine are really gone
 
Sudzy said:
Also, it was mentioned towards the end of this thread, that other fixed this problem by installing a new TRS (transmission range sensor) also known as a Neutral Safety Switch, and if believe there's another name for it,.....starts with a M??????
As for me, come payday, I'm going to try a new TRS and see.
Just thought I'd throw my thoughts at the problem... Is it possible, that there is more than just one issue going on here?
Click to expand...


hey, if you guys have the Clintons repair manual, it tells all about how you can ADJUST the manual level postion switch/transmission range sensor/neutral safety switch. Apparrently, they get out of alienment. Of course, the special tool that you need is $150, so you need to find a work around for that. I'll be working on mine tomorrow.
 
Damn, this thread is 4yrs in the making.

Thanks for all the info and for making your tests ect available.

Ill be trying new wires, coil pack and plugs this weekend

Cant really attest to the whole fuel level thing, as my car lives in the 1/2 to 1/4 tank range (college student)

One thing i can say is that regular cleaning of the MAF and throttle body help to keep this problem at bay.
 
just for S & G's check your lower intake gasket, found out today mine was leaking, my hesitation went away when i bought new wires but about a week later it was back but not as bad.
 
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