Hi new member here.. I just bought a 2000 Grand Marquis GS with 44K miles. It had set for a year after it's owner's death and they spent $1100 on a new fuel pump, tank cleaning, injector cleaning and a new filter for it to start after setting a year. I bought it and it had been running well. Filled it up with premium fuel and drive about 300 miles to that tank various speeds up to 80 but no hard acceleration. Ran great. Filled up at a quarter tank and after about 30 miles on the interstate hit 70 and it bucked and the check engine light flashed. Felt like it lost power and would not go any faster. I slowed down and pulled over car never stalled and light never stayed on.
Drove home but stayed under 55 and was fine. Still not quite as smooth as before but no issues.
Do you think the injectors are clogged again? or the filter???
Any suggestions? I was going to take it out and just floor it and let it get up to about 80 and see if it does it again. Maybe it needs to be blown out as it belonged to an elderly lady who drove pretty light??
Any advice would be appreciated!
Thanks
Chris

 

maybe there was some loose stuff in the tank or lines that partly clogged the fuel filter. Or cruddy gas possibly. It does sound like a filter needing changed, but what that causes is low fuel pressure. I'd put a fuel pressure gauge on it and test it at the speed where it's dropping out. Fuel use increases greatly as speed increases due to the increase in air friction being an exponential function (iirc).. it's not linear like the speed increase itself. That's why to get a car to *really* move, like racetrack speeds, takes a really hefty motor, most of the work is from shoving air out of the way.

Someone else did the work... so no telling how well it was done. Maybe they only said they cleaned the tank but didn't actually do it, figuring the filter would pick anything nasty out of the gas. Doesn't really work well, though. It could also be a defective fuel pump, or low supply voltage. Pressure gauges really are your friend, on fuel injected cars. Out of range fuel pressure = badly- (or non-) running car.

Cabby

 

Actually I'd see if I could find someone to pull the code (or get a cheap scanner and do it myself.) You could have a Throttle Position Sensor error or something else, unrelated to the fuel system. The code may tell you exactly what the problem is (there's normally a code set when the engine light comes on, relating to the problem that the control system detected that caused it to light the engine light up.

Good luck with it.
Cabby