I recently boughtan '84 Eldorado, 4.1 litre. When accelerating, she doesn't want to go with more than 1/4 throttle. When on the freeway, if you floor it, she down shifts, the motor revs up, and...nothing. no acceleration. Trans fluid is clear, no odor. I'm leaning towards a fuel issue, like the pressure regulator (ordered a throttle body rebuild kit), or a blocked catalytic converter. Any other thoughts? Just trying to cover all bases for trouble shooting. Thanks-

 

My 70 Deville is a different car but I had a similar problem and it was due to an exhaust blockage, colapsed double-wall exhasut pipe. My vote is a bad catalytic. Could be something else though I haven't heard much good about the 4.1 motor.

 

Just a shot in the dark here, do you have a single black or brown ground wire that attaches to your generator bracket??

 

I'm thinking the Cat is blocked as well. Might just try cutting it open, gutting it, and welding the cat back closed, or deleting the cat all together. Still gonna give her a good tune up, she runs pretty good considering. Thanks for the input~

 

It was just a severely blocked fuel filter. She's running strong now, or as strong as a 4.1 liter in a 4,000 lb car can run!