Contour Enthusiasts Group Archives Forums General Troubleshooting jerky acceleration..gotten worse

HI all..i've checked the search all over but can't find an exact symptom match...when accelerating from a stand still especially when warm the engine seems to cut out and in while the tranny is trying to shift from first to second..and RPM's go up and down greatly while this is happening...it does'nt feel like the tranny because it shifts fine but the engine jerks while its shifting. today 2 or 3 times when first taking off..before and forward motion happened the engine seemed to cut out totally for a second and the go smoothly...hopefully i've explained this enough and it makes sense..p.s. all tuneup items done recently and this is a atx zetec 1996

p.s. fuel filter also done twice to try to cure this frustrating problem..plugs wires etc..any help would be greatly appreciated

hey all...i hate to repost this but i can't beleive noone has any ideas on this problem...i've tried to help everyone out as much as i can but i need some help now..i'm sure someone has had this problem...HELP

How much gas is in the car when this happens? Although I have the 2.5 atx, mine sometimes does the same thing at WOT with a quarter tank of gas or less in it, esp. after a hard curve.

Have the fuel rail pressure checked out. The fuel pump may be getting weak.

I had a similar (sort of) problem, with my SVT between 4K and 6K RPM's. It became moticalbe with about 1/2 tank of fuel, and got progressively worse with less fuel in the tank.

Good Luck.

David

One area not yet explored may be a defective gas tank. Our 98 Mystique used to get that way on 1/8 of a tank or less. It was expained to me that the tank was defective and did not vent properly. The symptom was what you describe. The cause was that the tank not venting properly becam concave in the bottom and registered far more fuel than was in the tank essentially causing fuel starvation and an overly optimistic gas guage. It may be with a look see! P.S. the solution was a new gas tank!

John

unfortunatly it happens at any tank level..i really appreciate the input though....does it sound like it could be the tranny by any chance..i did'nt think so but other people have...it seems to not be dependent on any facto even engine temp. now...only at WOT it does'nt seem as bad...slower your going the worse it is...thanks again

I had a similar problem in which my car would learch forward and then pause (as if someone where hitting the brakes) and then learch again etc.
Get a Haynes manual and follow the instructionis for trouble shooting the fuel pump (they're pretty good). The main thing you'll need to do is get a fuel pressure guage (not too expensive) and hook it up to the fuel line (you may have to remove the air intake tube from the TB to do this..replace it once the guage is hooked up). Start the car. At idle the pressure should be around 27.5 psi (it gives a range in the book). Mine was about 19#! Anyway there is other stuff like removing the vaccumme from the fuel pressure regulator (kind of tough with the intake on) and see if the range is correct.
Anyway, I found out that the filter screen had fallen off my pump and into the gas take. Thus the pump and filter were fouled. I replaced both and everythings back to normal.

Similar, but perhaps different problem that seems to have some connection to acceleration. Afert a period of frequent accerating, not necessarily hard, but alot of reving through the gears, the engine just cuts out for a second, like the entire engine died for a second, but then it continues to run. None of the gauges or electrical aspects are impacted by the cut in the engine. It can happen once and then not happen for a long streach, then it may happen - the complete cut of the engine for a part of a second - a half a dozen times in a 60 second span. The "boys" at the shop seem to be at a loss..perhaps the most helpful thing they told me is that they view as a primary ignition problem...not secondary....it effects all four cylinders at the same time, it is not like only one is cutting out. Any thoughts? Mechanical - fuel related? Electrical - fuel related? Electrical - ignition? Please respond at jelliott@hunton.com

I have had the same problem on my '00 Mystique and have not been able to find any cause yet. The level of gas in the tank does not seem to be a prequalifier (happenes at all levels) but it seems to happen after taking a turn and then quickly accelerating. It almost seems as though the engine will stall but it doesn't and then the power kicks back in. If you have had any luck at a shop or found the answer to the problem I would be interested to hear about it. Good Luck