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hesitation/bucking is back

getsum111

Yes I am a Pirate, 200 years too late.
Joined
Apr 5, 2005
Messages
4,188
Location
Pillaging in Freedom, PA.
For those of you that have been following my dilemma, welcome to session 3!:mad: Got new wires last night, installed them, and checked my plugs. I still get a bucking/hesitation from off idle to about 3200 rpm's. I have checked most everything, but am willing to start checking again. Plugs are new autolite APP764, wires are/were Magnecore/Ford Racing/Taylors, swapped coil, MAF with known working ones, checked CPS, TPS. IMRC is working. So much else I really don't know. Any suggestions, as the car is going to be sold if I can't fugure this out soon. It happens whether the tank is full or not, so I don't think it's a fuel pump issue. Please help.
 
I had the same problem after installing new Motorcraft wires and plugs. It wasn't until I liberally coated the spark plug boots (inside and out) and the exposed part of the spark plugs with dielectric tune-up grease (Permatex) that the bucking/hesitation went away. Before I put the grease on, I made sure everything was clean.
 
I tried the dielectric grease, it didn't make a difference one way or another. When I pulled the plugs, they were still all white, which would seem to indicate I was not having a misfire, correct? Does anyone know which sensors would affect the ignition like this. I still am not getting any CEL, and the light does work. Which sensors should I check again? Thanks.
 
TPS maybe

TPS maybe

After searching, I have a feeling it could be the TPS. I have tested the resistance, but should I have checked the volts instead. As the hesitation occurs only at throttle in, maybe the sensor has a "part" that isn't reading/sending correctly. Does that make sense? Some people said that when their TPS went, it occured from off idle, that's what has me thinking this way. Opinions?
 
might as well check the voltage .... I believe it should range from 0.1 volts when closed to alittle less then 1 volt when open ...
 
TPS Volts: Volts should be between 0.2 and 1.4 volts at idle. At WOT volts should slowly rise to slightly less 4.8 volts.
 
For about a week, then the hesitation slowly returned. Now, I have to be very careful w/ the throttle or it will buck/stumble. It's still not throwing any codes, the plugs looked fine, ie insulators still white w/ no carbon marks or oil or anything. What are the symptoms of a TPS that is starting to go? I didn't get to check the TPS last night, prob try tonight after work.


P.S. I'm taking back my apology for doubting you! LOL
 
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You suck! I didn't say how long it would last. LOL! I've never had a TPS fail so I don't know.
 
Ha, Ha. Im really at my wits end here. A fuel pump going would affect the higher rev range correct? That is another test I'm gonna do tonight, even though I really don't think that's it.
 
Sounds to me the typical fuel filter clog scenario. When was the last time your replaced the fuel filter? If not replace it.
 
Bah! Bothers me when people note the filter. Hardly ever does anything unless the car has over 150k and has had a lot of bad gas. Your car does have the 99+ returnless pump with the issues. Has it been changed? It's really the only thing left. I bet if you pull it, ditch the screen and put anew pump in you'll be golden. It's only $100 and you won't have to worry about it again.
 
I've got an early 99, as it is a return system. Which should preclude the common fuel pump issues, and also use of the Focus smart pump.:cry: This weekend, I'm gonna do a test of the fuel pressure if I can get a pressure guage @ autozone.
 
You again! We should dedicate a forum just for you. :laugh:

Yeah, go through all the items that have been posted previously. I'm sure it has to be one of those. If not, please report back so that we have a better database to refer to. Thanks.
 
Hey Tony, long time no type.:laugh: Trust me, I feel bad hogging all the bandwidth to myself.;) Man this is soooo frustrating. I've never had any trouble w/ the car, or I was always able to repair it myself, and now I can't get this problem even diagnosed.:cry: Makes me sad, as I still have my X-mas present to install (new glasspack instead of res.)
 
Hey Tony, long time no type.:laugh: Trust me, I feel bad hogging all the bandwidth to myself.;) Man this is soooo frustrating. I've never had any trouble w/ the car, or I was always able to repair it myself, and now I can't get this problem even diagnosed.:cry: Makes me sad, as I still have my X-mas present to install (new glasspack instead of res.)
LOL. So long as we are still alive and kicking, we will try to help. :) Every now and then, even we get stumped. Hang in there, you will get it fix!

Er....., hold off on the glasspack install for now. You don't want to throw in a monkey wrench in the system. It might muddy the issue.
 
just to verify has it been checked to see if the pre-cats or the main cat is clogged up at all ... might explain why at low rpm there is a hesitation but at high rpm there isn't anything :shrug:

just a thought that hit me
 
No, the glasspack waits. I don't want it to sound like I can't drive a stick.:laugh:

Brian, no I didn't check that, but shouldn't they throw a code? I did have a vac. leak for a couple days, back in Nov. :shrug: Maybe I'll do the "el cheapo" clogged precat test tonight.:laugh: Boy, that would give me an excuse to get the headers that go on sale next month.;)
 
No, the glasspack waits. I don't want it to sound like I can't drive a stick.:laugh:

Brian, no I didn't check that, but shouldn't they throw a code? I did have a vac. leak for a couple days, back in Nov. :shrug: Maybe I'll do the "el cheapo" clogged precat test tonight.:laugh: Boy, that would give me an excuse to get the headers that go on sale next month.;)

no I don't believe a plugged cat would set a code ...
 
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