Help my car will not rev over 3500 rpms

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Isaac-1

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Sep 8, 2001

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SW Louisiana

Oct 21, 2004

#1

• Oct 21, 2004

• #1

Something is wrong with my 99 GT, after I have been driving some distane (100+ miles) the engine will not pull, I can even drop it into nuetral and give it WOT and it will not rev over 3000-3500 rpms. It does not trip any codes, it just will not go, it revs up to around 3500 rpms then sputters. Does anyone have any ideas? I am thinking maybe the fuel pump/fuel pressure sensor if it has one. The problem will go away for a while if I turn the engine off for as little as 1 minute (stopped at redlight, etc). This has been going on for about 6-8 months, but keeps getting worse(shorter driving distance before it starts, when the problem first started I had to drive for 300-400 miles before it showed up). Does anyone have any ideas?

Thanks Ike

 

2001Saleen181

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Mar 20, 2004

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Oct 21, 2004

#2

• Oct 21, 2004

• #2

Sounds like a possible clogged fuel filter.
When you shut the car off, the dirt probably settles until you start the car up. This is just a guess.

 

AirWolf87

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Oct 21, 2004

#3

• Oct 21, 2004

• #3

yeah realy does sound like a clogged fuel filter or a bad pump. Simple, if your engine isnt getting the fuel it needs, it wont rev...it will reach a sertain point where it starves iself (would cause sputtering) try replacing the filter first. its a cheap place to start trouble shooting

 

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Isaac-1

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Sep 8, 2001

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Oct 21, 2004

#4

• Oct 21, 2004

• #4

I changed the fuel filter out after this first started happening about 8 months ago, it made no difference the next time I took a long trip.

Ike

can anyone think of anything else it could be other than the fuel pump?

 

2001Saleen181

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Mar 20, 2004

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Oct 21, 2004

#5

• Oct 21, 2004

• #5

If your fuel rail has a schrader valve like mine does, you can hook up a fuel pressure gauge and see what kind of pressure you are getting. This should help with trouble shooting.

 

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Isaac-1

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Sep 8, 2001

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SW Louisiana

Oct 22, 2004

#6

• Oct 22, 2004

• #6

I bought a cheap fuel pressure gauge at an autoparts store on the way home tonight. Fuel pressure with ignition switch one engine not running is a solid 35 psi, with engine running at idle it flucuates between 42-46 psi (slightly less than 1 second cycles), reving the engine seems to make it settle down closer to 40 psi. Over the weekend I may take it on a 75-100 mile drive to see if it starts acting up and test it again.

Ike

 

AirWolf87

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Mar 14, 2004

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Oct 23, 2004

#7

• Oct 23, 2004

• #7

let us know

 

crew_dawg16

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Apr 25, 2004

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Oct 23, 2004

#8

• Oct 23, 2004

• #8

clogged catalytic converter(s) I had the same problem with my '86 trans am. It keeps getting worse until it won't even idle.

 

AirWolf87

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Oct 24, 2004

#9

• Oct 24, 2004

• #9

crew_dawg16 said:

clogged catalytic converter(s) I had the same problem with my '86 trans am. It keeps getting worse until it won't even idle.

Click to expand...

i didnt even think of that. Ive never had or seen this happen, but it sounds like it would cause those simptomes....check the fuel system, if you dont find any signs of bad fuel delivery (judging by your pressure doesnt sound like you do) go check the cats.

 

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Isaac-1

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Sep 8, 2001

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Oct 25, 2004

#10

• Oct 25, 2004

• #10

Ok here are the results so far, I took the car on a 50+ mile drive, it started acting up after about 45 miles. I then stopped in at a friends house and connected the fuel pressure test gauge without killing the engine, at idle the pressure was 39-40 psi, however when revved it would drop to the 33-35 psi range, a big difference from the friday night test that was done after 15 miles of driving with a 10+ minute cool down.

Ike

p.s. I plan to change out the fuel filter in the morning (weather permitting), just in case that is the problem, other than the fuel pump, does anyone have another suspect?

 

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vervuurt

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Jan 1, 2011

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Jan 1, 2011

#11

• Jan 1, 2011

• #11

Did you find the solution to this problem?
I'm having the same problem with my 00 GT

 

Sonic04GT

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Nov 1, 2009

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West Palm Beach, FL

Jan 1, 2011

#12

• Jan 1, 2011

• #12

vervuurt said:

Did you find the solution to this problem?
I'm having the same problem with my 00 GT

Click to expand...

Not sure if you realized, but this thread is about 6 years old. You probably won't get the response you're looking for lol

Isaac-1 hasn't signed on in 2 years.

 

wmburns

SN Certified Technician

Aug 14, 2009

5,892

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204

Houston Texas

Jan 2, 2011

#13

• Jan 2, 2011

• #13

FWIIW, this could also be from over heating. The later MY cars have something called Failure Mode Effect Management (FMEM). FMEM affects how the PCM responds under different failures.

The FMEM for overheating is to restrict timing advance. This limits engine RPM and heat output. The idea is to allow an overheating car to be driven slowly off the road. IE, it's better to drive slowly instead of stuck or ruining a motor.

It seems to me that a faulty temperature sensor could also cause the PCM to engage overheating FMEM even if it's not overheating.

The could also be a clogged cat as well as a fuel pressure problem (bad pump or sensor).

 

1995GTStang

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Feb 9, 2009

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Washington State

Jan 2, 2011

#14

• Jan 2, 2011

• #14

I agree with WMBURNS
if anyone in the future starts having similar problems, I would recommend starting with a new fuel filter....approx 12-15.00 and it only takes about 10mins to swap out. If that does not eliminate the problem, work your way forward. With the car running see if you hear any vibrations coming from the catalytic converters. Also take the handle end of a hammer or a small block of wood and tap on them. If you hear something moving around chances are they might be plugged. If no luck with either one of those, run a fuel pressure test.

 

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vervuurt

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Jan 1, 2011

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Jan 4, 2011

#15

• Jan 4, 2011

• #15

Im thinking about removing the cats tomorrow, dont have to go through emission tests where im from!