1998 Cadillac DeVille "truck runs rough 55" Questions

...runs great.......I hope this helps. I know its probly a temperary fix but its a fix and now we know what the problem was. SASSY That sure sounds like a headgasket failure even if the engine recovers ...

runs rough when running at 45 to 55 mph car out of cruise control flutters or runs rough from 45 mph to 55 mph and once over 55 mph runs smooth. I notice from 45 to 55 the rpm guage moves with flutter

...rough and getting worse. when we read the code using the key turn trick, it comes up 12 13 55. can anyone help me find out what this means? code 12 is start 13** No difference recognized between the ...

...4.3 v6 tbi runs fine in park wen at stop lights in drive it feels like its starving for fule running rough it also runs rough at 50 55 mph and im getting bad gas milage replace coil packs and tune ...

...runs rough from 45 mph to 55 mph and once over 55 mph runs smooth. I notice from 45 to 55 the rpm guage moves with flutter or rough running engine. when i put in cruise control it smooths out. Flush ...

...rough and rich problems start. No codes. I also have high fuel pressure at the rail. About 55 psi? any ideas? fuel pressure seems a bit high...could be a bad regulator. can't remember if yours is on ...

...RUNS REALLY ROUGH LIKE STARVING FOR FUEL TROUBLE CODES P0263 P0336 PO401 PB2B P2763 just a guess but might be a fuel pump, try smacking the tank before you start it and see if it idles better

...runs rough with no codes Runs rough no codes, fuel pressure bouncing between 55-60 psi, replaced crank sensor with updated cps, No signs of fuel coming out of regulator, no obvious vacuum leaks map ...

...runs rough between those speeds, if i give it lots of gas it seems to run ok but not perfect. sounds like you might have either a fuel filter issue, or just needs a tune up. i would check with a auto ...

...runs rough and dies when gas pedal pushed to floor. Blazer was running fine then when on the highway the engine sputtered and had to pump the gas pedal to get a couple blocks off the highway. Car ...