performance of car continuing to fade away

richie · 08-21-2001, 10:36 AM

I have asked this question before in the past about the performance of my car is not what it used to be.My stang for the last year has slowly been loosing power.Everytime I think I have found or fixed the problem I havent.I have replaced every ignition component except for the distributor itself.The fuel pressure is good and so is compression.I have also changed the fuel filter,plugs-autolite 24's,wires-taylor spiro pro.My gas mileage sucks to at 11mpg.i replaced the o2 sensors and added underdrives to hepl with mileage but they didn't help.The car doesn't have the power at all rpms,but it idles smooth and doesn't blow any smoke.I once did a leakdown test a few months ago but can't remember the exact results.They dial on the gauge was in the green low area.I hooked up a vacuum gauge to the intake and vacuum stays at a steady 17psi and goes up like it should when revving the engine up.The only things I think could be causing this loose of power are a bad fuel injector,clogged cats though the vacuun gauge was fine but that wasn't when driving.I also though maybe my valve seals are bad but the car doesn't smoke and its not a high rpm problem its at all rpms the car sucks.My stang is at least 10 miles per hour slower at any speed and in any gear.I am at a loose and need help.

Sneaky · 08-21-2001, 01:23 PM

What year, milage does your car have? Have the Cats ever been changed or hollowed out? If it is not burning oil or smoking, then I would look at the cats as the culprit, but with poor fuel milage I would also suspect the injectors.

Mr 5 0 · 08-21-2001, 01:44 PM

You neglected to give the year, mileage and mods on your Mustang, but generally speaking,
clogged cats could very well be the culprit - or - you may have a Mass Air Sensor going bad on you, although that would (should) trigger the dreaded 'Check Engine' light.
Try some Ford injector cleaner (only available at Ford dealers - about $10. - good stuff). If that results in any improvement, you know it's quite likely a case of clogged or otherwise failing fuel injectors.

[This message has been edited by Mr 5 0 (edited 08-21-2001).]

richie · 08-21-2001, 02:15 PM

The mileage is 137,000 and the mods are 3.73's,flowmaster exhaust,asp pullies,march ram ram, koni yellow struts,,130amp,alternator.The rest of the car is stock.I had the injectors cleaned with the type that the car runs off of and tthat did nothing.The car used to vary every once in a while on how much power is had but now it just doesn't accelerate like it used to.I just bought a noid night to test current to the injectors but can't get the harnesses off.I also bought some longer tubing for my vacuum gauge so I can run it into the car to test vacuum while driving.How can I test the injectors to know if there flowing properly?The cats have never been replaced or messed with at all.The car is a 89gt 5sp.

08-21-2001, 10:36 AM	#1
richie Registered Member Join Date: Apr 2001 Posts: 47	performance of car continuing to fade away I have asked this question before in the past about the performance of my car is not what it used to be.My stang for the last year has slowly been loosing power.Everytime I think I have found or fixed the problem I havent.I have replaced every ignition component except for the distributor itself.The fuel pressure is good and so is compression.I have also changed the fuel filter,plugs-autolite 24's,wires-taylor spiro pro.My gas mileage sucks to at 11mpg.i replaced the o2 sensors and added underdrives to hepl with mileage but they didn't help.The car doesn't have the power at all rpms,but it idles smooth and doesn't blow any smoke.I once did a leakdown test a few months ago but can't remember the exact results.They dial on the gauge was in the green low area.I hooked up a vacuum gauge to the intake and vacuum stays at a steady 17psi and goes up like it should when revving the engine up.The only things I think could be causing this loose of power are a bad fuel injector,clogged cats though the vacuun gauge was fine but that wasn't when driving.I also though maybe my valve seals are bad but the car doesn't smoke and its not a high rpm problem its at all rpms the car sucks.My stang is at least 10 miles per hour slower at any speed and in any gear.I am at a loose and need help.

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08-21-2001, 01:23 PM	#2
Sneaky Registered Member Join Date: Aug 2001 Location: Baytown, Tx. USA Posts: 25	What year, milage does your car have? Have the Cats ever been changed or hollowed out? If it is not burning oil or smoking, then I would look at the cats as the culprit, but with poor fuel milage I would also suspect the injectors.

08-21-2001, 01:44 PM	#3
Mr 5 0 Conservative Individualist Join Date: May 1997 Location: Wherever I need to be Posts: 7,487	You neglected to give the year, mileage and mods on your Mustang, but generally speaking, clogged cats could very well be the culprit - or - you may have a Mass Air Sensor going bad on you, although that would (should) trigger the dreaded 'Check Engine' light. Try some Ford injector cleaner (only available at Ford dealers - about $10. - good stuff). If that results in any improvement, you know it's quite likely a case of clogged or otherwise failing fuel injectors. [This message has been edited by Mr 5 0 (edited 08-21-2001).]

08-21-2001, 02:15 PM	#4
richie Registered Member Join Date: Apr 2001 Posts: 47	The mileage is 137,000 and the mods are 3.73's,flowmaster exhaust,asp pullies,march ram ram, koni yellow struts,,130amp,alternator.The rest of the car is stock.I had the injectors cleaned with the type that the car runs off of and tthat did nothing.The car used to vary every once in a while on how much power is had but now it just doesn't accelerate like it used to.I just bought a noid night to test current to the injectors but can't get the harnesses off.I also bought some longer tubing for my vacuum gauge so I can run it into the car to test vacuum while driving.How can I test the injectors to know if there flowing properly?The cats have never been replaced or messed with at all.The car is a 89gt 5sp.