dodgethis Posted May 8, 2014 Report Share Posted May 8, 2014 Ok, This morning I go out to vehicle and prime the car up as usual, and try to start it. It didn't catch the first time, so I start it again. I hear a thud/pop noise under the vehicle and it starts miss firing. The RPMS ramps all the way up to 5000, to 6000 RPMs, and falls back down, and dies. I can hold the gas pedal and it will shoot all the way back up to the mentioned RPM range, and try to die again. I thought what I herd would have been maybe the PCV boot popped off, and the engine is running rough. To my surprise everything is still hooked up. Now, here he are with a sick 3100sfi. I understand the next step would be to pressure check each cylinder. I don't have one, but could I tell anything if I started to pull all spark plugs out? I don't have a check engine light, as the car won't stay running long enough. I have religiously changed the oil, and tranny fluid. Quote Link to comment Share on other sites More sharing options...
dodgethis Posted May 8, 2014 Author Report Share Posted May 8, 2014 I checked the dipstick, there isn't any metal debris. I pulled the spark plugs, and they look fine, as no cylinder slapping the electrode, or oil coated. I just have to keep fighting to hold the gas pedal down to keep it running. The RPM's keep ramping high, and then it will try to stall out. I think the engine is fine, but does a TPS do this on the way out? I just replaced it not long ago. It still has the original IAT sensor. Can the crankshaft sensor do this? I tried putting in park, but its bear to keep it running while driving it around. I don't have a check engine light. Damn, what a challenge. Quote Link to comment Share on other sites More sharing options...
Galaxie500XL Posted May 8, 2014 Report Share Posted May 8, 2014 A large vacuum leak could do similar things...my first suspected culprit for a large one would be the power brake hose/booster. I'd block that sucker off, and see if things look more normal. Quote Link to comment Share on other sites More sharing options...
dodgethis Posted May 8, 2014 Author Report Share Posted May 8, 2014 A large vacuum leak could do similar things...my first suspected culprit for a large one would be the power brake hose/booster. I'd block that sucker off, and see if things look more normal. Galaxie! your a genius sir! I can't believe I overlooked that! The only time I have seen vacuum cables popped off is the PCV gromet. She started right up and is calm as ever. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted May 8, 2014 Report Share Posted May 8, 2014 huh...... must have had a pretty significant backfire to pop that off or maybe a missing clamp? Quote Link to comment Share on other sites More sharing options...
Galaxie500XL Posted May 8, 2014 Report Share Posted May 8, 2014 An awful lot of people never put that clamp back on, but what makes it worse, is usually the hose after a few years has been exposed to enough stuff that it's really soft. Makes it much easier to pop off if the clamp is missing, or, like what happened to my Cutlass, the brakes are terrible because the hose is collapsing. Quote Link to comment Share on other sites More sharing options...
cutlassdude96 Posted May 9, 2014 Report Share Posted May 9, 2014 mine has done that a few times Quote Link to comment Share on other sites More sharing options...
dodgethis Posted May 10, 2014 Author Report Share Posted May 10, 2014 huh...... must have had a pretty significant backfire to pop that off or maybe a missing clamp? Brake booster vacuum tube once had a clamp? I never seen one, not on this car at least :dunno: Quote Link to comment Share on other sites More sharing options...
dodgethis Posted May 10, 2014 Author Report Share Posted May 10, 2014 An awful lot of people never put that clamp back on, but what makes it worse, is usually the hose after a few years has been exposed to enough stuff that it's really soft. Makes it much easier to pop off if the clamp is missing, or, like what happened to my Cutlass, the brakes are terrible because the hose is collapsing. Now that's interesting, the hose is very soft, I'll look into getting a new hose, and a clamp for it Quote Link to comment Share on other sites More sharing options...
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