that can't diagnose the problem and have changed a million parts and it still don't run right.......
my car started doing that and I too was trying to figure out what was wrong.  so I got it down to feul press reg., feul pump strainer, feul filter, or just unknown.  decided to go with the cheapest/easyiest fix first.  the feul filter.
it wasant so much the filter, but when I disconnected it something just diddn't smell right.  when I got the filter off I held it up and only a few drops came out.  so I cleaned of one end and blew on it as hard as I could.  most people don't do the blow test on an old feul filter but I do for this reason.  (keep in mind this filter is not very old)at first I couldn't blow through then all of a sudden it felt like something pushed loose and a @!#$load of black fluid came out.  then I could almost blow freely through the filter.  so I just went about putting the new filter on, started the car, and backed it up to see what I left on the ground.
now my driveway is white concrete.  and on a hot day feul (which is clear) just hits the ground and evaporates.  well, I now have a jiant black circle in my driveway from where I blew out the filter.  and you could actually follow the trail from where I disconnected it and let the system drain, to where I carried it to do the blow test.  there are little black smudges everywhere.
new prognosis, sludge in the tank, probobly from a bad feul tank at a gas station.  the studder is almost non-existant now becouse instead of dropping the tank I just decided to get a bottle of sea foam, fill up the tank, and just run that @!#$ out.  this may sound like a bad idea but now everytime  I drive it it runs a little better.  I still have a 3/4 tank of 'contaminated' feul so we'll see
hope this may help some of you out there with this unfixable studdering problem
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when you beat someone in a civic people wine and make excuses
when you beat someone in a cavalier they pull over and check under thier hoods