I've read the other threads, especially 173 (Bucking and Killing), my problem "seems" to be unique, so I started a new thread, I have spent months and $100s trying to fix this problem.
MercuryCougar 1999 with Zetec engine and MTX transmission is kicking or bucking, thisis not knocking or hesitation it’s much worse. Bucking is most prominent whenin 4th gear at highway speed going downhill when I have foot off the acceleratorthen accelerate hard, sometimes the car will buck multiple times – then I haveto press in clutch then feather it back down for bucking to stop.
Problem alsooccurs
1. Duringmedium to hard acceleration from stop
2. Inany gear when accelerator pedal goes from 0 position (foot off pedal) to rapidacceleration
3. Sometimesit happens seemingly for no reason although this seems to be more common goingover bumps.
Problem doesnot occur
1. Ihave foot off gas pedal (throttle) then floor it when I in 5th gear goinguphill and does it just slightly when going downhill, it will buck in othergears.
2. Itseems to hesitate a little when the throttle is at say 10% position thenpressed hard.
3. Itdoes not buck when I have transmission out of gear
Car alsobadly lurches/bucks when I take foot off gas pedal (throttle) at very low speeds
I haveperformed the following without the problem going away:
· Checkedfor vacuum leaks carburetor cleaner with engine cold
· replacedthe throttle position sensor
· airfilter changeout.
· Coilpack was replace a year ago and car had this problem before and afterreplacement.
· Ihave tried 2 bottles of Chevron Techron fuel system cleaner,
· fuelingwith 93 Octane Shell gas, I normally buy shell regular unleaded.
I tested theclutch while stopped at idle. I drop theclutch in 4th gear and the engine stalls instantly. Interesting, the buck I feel is very muchlike the buck that I am complaining about. Also the engine doesn’t race up and down while in gear, there does notseem to be any signs of slipping clutch. Note the throw-out bearing rattles sometimes when I’m stopped at idle,when I push clutch in and let it out again rattling stops.
Dealercharged $115 for mechanic to run a series of diagnostics including thecomputerized diagnostic tool which came back with no fault codes. His only suggestionswere to do the following which I did:
· Replacespark plugs and wires
· replacestuck PCV valve and PCV tube that was said to be "collapsed".
I did all he suggested. He said he did not think there was a problem with clutch or engine mounts. More likelycauses that I have not looked into:
· Checkedfuel pump, or
· Cleanedfuel injectors - the fact that PCV valve has been stock means injectors couldbe quick dirty/clogged and probably need cleaning.
· Could it be engine or transmissionmount(s), I looked at front one it looks OK? Also haven’t looked at transmission mounts.
Thanks,
PS
I'm in Washington DC area where most people work directly or indirectly from the government and use their salary to buy foreign cars.
MercuryCougar 1999 with Zetec engine and MTX transmission is kicking or bucking, thisis not knocking or hesitation it’s much worse. Bucking is most prominent whenin 4th gear at highway speed going downhill when I have foot off the acceleratorthen accelerate hard, sometimes the car will buck multiple times – then I haveto press in clutch then feather it back down for bucking to stop.
Problem alsooccurs
1. Duringmedium to hard acceleration from stop
2. Inany gear when accelerator pedal goes from 0 position (foot off pedal) to rapidacceleration
3. Sometimesit happens seemingly for no reason although this seems to be more common goingover bumps.
Problem doesnot occur
1. Ihave foot off gas pedal (throttle) then floor it when I in 5th gear goinguphill and does it just slightly when going downhill, it will buck in othergears.
2. Itseems to hesitate a little when the throttle is at say 10% position thenpressed hard.
3. Itdoes not buck when I have transmission out of gear
Car alsobadly lurches/bucks when I take foot off gas pedal (throttle) at very low speeds
I haveperformed the following without the problem going away:
· Checkedfor vacuum leaks carburetor cleaner with engine cold
· replacedthe throttle position sensor
· airfilter changeout.
· Coilpack was replace a year ago and car had this problem before and afterreplacement.
· Ihave tried 2 bottles of Chevron Techron fuel system cleaner,
· fuelingwith 93 Octane Shell gas, I normally buy shell regular unleaded.
I tested theclutch while stopped at idle. I drop theclutch in 4th gear and the engine stalls instantly. Interesting, the buck I feel is very muchlike the buck that I am complaining about. Also the engine doesn’t race up and down while in gear, there does notseem to be any signs of slipping clutch. Note the throw-out bearing rattles sometimes when I’m stopped at idle,when I push clutch in and let it out again rattling stops.
Dealercharged $115 for mechanic to run a series of diagnostics including thecomputerized diagnostic tool which came back with no fault codes. His only suggestionswere to do the following which I did:
· Replacespark plugs and wires
· replacestuck PCV valve and PCV tube that was said to be "collapsed".
I did all he suggested. He said he did not think there was a problem with clutch or engine mounts. More likelycauses that I have not looked into:
· Checkedfuel pump, or
· Cleanedfuel injectors - the fact that PCV valve has been stock means injectors couldbe quick dirty/clogged and probably need cleaning.
· Could it be engine or transmissionmount(s), I looked at front one it looks OK? Also haven’t looked at transmission mounts.
Thanks,
PS
I'm in Washington DC area where most people work directly or indirectly from the government and use their salary to buy foreign cars.