Fuel delivery or trans??
 

my Coupe('91) revs fine in neutral and park, but when the throttle is about 2/3 or more open in gear(most noticeable in the top of 3rd, around 40 mph) it surges. Also, when i STAND on the throttle and it kicks down, nothing. No power, you can just hear the engine stutter. Normal acceleration is fine, except the aforementioned surging near the top of the gears Is this a fuel delivery problem(maybe sending unit, TB, injectors) or transmission problem?
Thanks again
~'91 Coupe DeVille, banana yellow

sounds like an overdrive problem.. try doing manual shift, the 1st, 2nd,3rd, and take the car over the 40mph without going into overdrive..... let the forum know what happins
rickyd

check fuel pressure.
none of that sound like the trani.


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if i remember right my 92 deville did the same thing and i ended up replacing my Fuel pump. does it do it when you have a certain amount of gas in the tank? cuz mine did it everytime i hit 8 gallons left and if i filled it full it was fine. Then it got worse overtime.

Replace the fuel filter first, probably original, then perform a fuel pressure test. Sounds like lack of proper volume of fuel reaching the engine.

I changed the fuel filter before I even started it the first time(sat 2 years), pressure was good and injectors were good... oh and manually shifting didn't help much, kind of amplified the shuddering when i got over 2500 RPM... ran diagnostic and the DISTRIBUTOR is bad! Found some @ the junkyard(better than $150 for a reman and $450@ the dealership)...
Now how easy is it to replace the distributor on the 300ci? anyone done it? I'm assuming it's more complicated than it looks, hence the $300 labor charge:D
sorry for the late reply.....
~N8

last time i changer distrubutor was on my boat, a mallory dual point. all i remember is having to line it up right. maybe someone else can jump in on this one. good luck, i hope you've found the prob.....
rickyd

Yeah, Just getting #1 to TDC and lining everything up seems to be the most difficult part; I hope this is the fix too! I'm sick of limping a sick baby to work!