FX seems so slow all of a sudden...loss of power...?

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brown_fv

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Toronto, On
for the past few nights every time ive been driving my FX it seemed to be a lot more sluggish and a lot slower than it usually is...when i hit the gas i feel like there is no low end power whatsoever and something that i really noticed is that i barely hear the whistle of my pop charger that i usually do. the filter doesn't need cleaning as i only have around 5000km on it.

when i turn on my car in the garage i hear this faint high-pitched sound...could it possibly be an air leak from my plenum? i remember a few nights ago i was just re-tightening the bolts...maybe i broke one? would an air leak cause a noticeable loss of power the way i am feeling it? it honestly feels slower than stock:frown:

i am due for service in a little bit, but i am very hesitant to bring it up as i am modded and there are not so many modded cars here (i might be one of the only modded FXs in the city)

btw if it means anything, when i turn on my FX the RPM shoots up over 2000 before settling (cant remember if it did that before)

thanks.
 
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A leak could be your problem or it could be something simple like bad gas. If you are hearing a hissing noise that wasn't there before I would start checking leaks. BTW what's the mileage on your FX?
 
Yes a leak could cause sluggish power due to the un-metered air entering the engine. I always check for leaks by spraying some fuel injector cleaner around the areas I think I have a leak and if the idle changes when you spray you have found your leak.
 
fxlr8 said:
Yes a leak could cause sluggish power due to the un-metered air entering the engine. I always check for leaks by spraying some fuel injector cleaner around the areas I think I have a leak and if the idle changes when you spray you have found your leak.
Click to expand...
if i want to try this, should i first turn on my car and while it is already idling just spray a slight amount over the area (or areas) where i think a leak could be? how will the idle change? will the fuel injector cleaner get sucked in?
 
Here is something I pulled off the web


Troubleshooting:
Vacuum Leak Diagnosis and Repair.

[Inquiry]Anyone know of a good method of test for and locating vacuum leaks in the the air intake system?
  • By Listening. [Response: Don Foster] Find or buy a 3' length of new fuel hose. Stick one end in your ear and snoop around the intake system with the other end listen for any pronounced hisssssssing. [Warren Bain] I was able to isolate a vacuum leak with a mechanic's stethoscope with the probe removed and only using the tubing to get very close to the gasket and follow the contour of the manifold. You can also modify the stethoscope for locating vacuum leaks by replacing the probe with a length of plastic hose or fuel line.
  • Spraying With Liquid. Another trick, for small leaks such as loose intake manifolds or shrunken injector seals, is to spray them with carb cleaner. This will temporarily seal a leak and a rough idle will smooth out for 10-15 seconds: you will hear the change in idle rpm.
  • Using Propane to Alter the Mixture. [Tip from Bruce Young] I use Propane to test for vacuum leaks It's as safe (or safer) and less messy than spraying carb cleaner or other flammables . Take the nozzle tip off a propane torch and replace it with some snug fitting rubber hose about 2 feet long. Practice with the valve to get a moderate gas flow (not a roaring blast). With the engine at a warm idle, open the gas valve and poke the end of the hose around each injector for a couple of seconds. If the seals leak, you should hear an RPM change when the propane gets sucked in and burned. Do the same around any other suspected areas, like hidden vacuum hose ends and the intake manifold gasket itself. To block the breeze from the fan, lay a piece of cardboard from the fan shroud to the engine.
  • Using Smoke to Locate Vacuum Leaks. Filling the intake system with slightly pressurized smoke from a smoke generator will allow you to see leaks where the smoke emerges.
Click to expand...


Yes, start the car first and at idle do the above
 
ok, i got some fuel injector cleaner and did what you said. before i did that i loosened me plenum bolts then torqued them back into place. at idle when i sprayed the fuel injector around some of the bolts or areas i thought could have a leak i did not hear any change in idle. my gas is almost empty so ill fill her up at a different station today and see if maybe there was a batch of bad gas or something.
 
well ever since then ive noticed its not as "sluggish" as it was before but still feels like something is missing. i dont hear that noise i heard coming from the engine before, i guess i should have used the fuel injector cleaner before i re tightened all the bolts, but im pretty sure one or more were loose. when i turn on from a cold start engine shoots to no more than 2000 rpm or so and then settles (before it was going well past 2000rpm). i also hear my pop charger again...will try to do some 0-60 tests (estimates as i dont have a g-tech or anything) and a bunch of WOT pulls to see if everything is back to normal.
 
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