OK, I have a 1998 Grand Marquis with about 314k miles, i think cause the dealership put like half of that on my paperwork. Its the LS with all the digital dash and all. OK my check engine light is on but this is the problem. When i press the pedal all the way down its stalls and starts to slow down, and i have to push the pedal a certain wayto get it to speed up. Like if i just push the pedal it will move alil but if i push it and move my foot off alil then it speeds up and not a lot. Whats going on with my car...[img]smileys/smiley19.gif[/img] Edited by: joegee82

 

314K on a 1998? [img]smileys/smiley3.gif[/img] r u kidding man?

 

I have the same problem my 1998 MGM has 268K and it does the same thing. I recently replaced some parts on the ignition coil. the springs with new boots. it ran alot better ,but still is doing it alittle bit. I have one more spring and boot to replace for it to be a whole set replacement. I hope this helps. it was about 4.00 for each spring assembly for each coil. they ran out at the parts store so I only replaced 7 of the eight and it helped out.

 

Alright, 314k, if you press the gas pedal all the way down it stalls and begins to slow down. Sounds logical to me. Dirty IAC and a broken catalytic converter could cause sucha dilemma? I think it's time for a engine swap or the bone-yard.

 

dang how you guys get a car to go that many miles...i didnt know anything last that long [img]smileys/smiley17.gif[/img]

 

keep on truckin brother. don't let the 314K hold you back. I have 268K and the motor has great compression and still passes the emissions. I also hook seafoam fuel injector cleaner with a hose and connect it through my brake booster vaccum. it goes directly into the injectors and also cleans out the converter a little. I use a regular 2 feet long gas line and then in the end of it I put a smaller vaccum line so the brake booster will not suck the whole can in a second. It kept my injectors clean, catlyatic converter and valves for 268K. They are all original and the car really runs good for the mileage.Sure the motor is a little tired from almost 300K but it really runs great still. Try the new ignition springs for the coils and then something to clean out the injectors. My guess is that the fuel pressure regulator might also be the problem. I think you will want 30-45 psi in the fuel regulator if you are going to check it.

 

so what is the verdict joegee?

 

Just sounds like some fuel delivery maintenance is needed... possibly a new fuel filter as well?

I have 140K on my 98 and it still runs great. Starts hard in the winter with 93 octane (I run 89 in the winter and it helps starting a lot), but other than that, looks great, rides great and runs great.

 

with gas so high i may have to keep mine forever....prolly not gonna be a good resale for these big rides now...i might getfind out if mine will last 200k [img]smileys/smiley17.gif[/img]

 

sounds like a fuel management problem possibly. i would drop the tank and replace the fuel ump fiter/sock in the tank, replace the "O" ring gaskets on the tank and get the fuel filter replaced that is located on inner side of frame passenger side.