4.6 Engine Boggs Down over 3000 RPM

captnapi · 12-01-2005, 10:39 AM

4.6 Engine Boggs over 3000 RPM
1997 GT 4.6 Automatic Trans

Perfect idle – Starts perfectly – No engine light - Runs perfectly

But… Over 3500 to 4000 RPM’s the engine just dies like it’s starving for gas.

I changed the fuel filter and it helped ever so slightly but I still can’t push the engine over 4000 RPM. I don’t think this has anything to do with my problem but I also noticed the transmission refuses to shift when it bogs down @ 4000 RPM. I’m guessing when the engine boggs the vacuum insufficient to shift the transmission.

Anyone ever experience something like this? If anyone that could point me in the right direction it would be greatly appreciated.

jeredan2003 · 12-01-2005, 12:42 PM

Doesnt really sound like a tranny problem to me. Could be your fuel pump. I had one go bad on mine and I have an 03. Go and find a fuel pressure tester. There should be a schrader valve on one of your fuel rails. Thats where the guage hooks up to. Hook it up with the car off then start the car after its hooked up. Look at the pressure while the car is at idle. Just follow the directions and you car should be at a constant 39-45psi. If its below that then you definately have a weak pump.

ponyexpress96 · 12-01-2005, 12:55 PM

yes i agree with the presure test always a good place to start but i also agree most likely the pump

captnapi · 12-02-2005, 04:17 PM

Thanks for the advice Fellas.
It's really a 99 GT. confused it with my 97 Expedition.

Are you referring to the injector’s pressure?

Do I still check the fuel pressure on the fuel rail in the same spot and with the same pressure for a 99?

Do you know the type and size fittings on the fuel rail? If at all possible, I want to use my Snap-On Compression tester with an adaptor. By chance do you know a part number I would need?

Thanks for your suggestions…

ponyexpress96 · 12-03-2005, 06:10 PM

yea i would check at the rail and i dont konw if you can use ur compression tester to test the fuel rail when i dont it i used a fuel pressure gauge but that was all it was able to due but urs could diffrent cause snap-on has so much diffrent stuff Are you asking where ?

if so there sould be a screw at the end of the fuel rail or a little thing in the end you can unscrew

captnapi · 12-04-2005, 05:22 PM

I know I need a fuel pressure tester that was kinda a stupid question.

I finally had a day off to look at the fuel rail. It’s a Schrader valve, like the one your tires.

Well, believe it or not the problem I was having just disappeared? I think there may have been water in my gas. Only time will tell but at least it buys me some time to pick up a fuel pressure tester.

Thanks for the suggestions! If the problem resurfaces I’ll get serious and tackle it then kinda FYI everyone since you were kind enough to help.

Happy Holidays Everyone….

wpgfordguy · 12-04-2005, 06:26 PM

Quote:

Originally Posted by captnapi

I know I need a fuel pressure tester that was kinda a stupid question.

I finally had a day off to look at the fuel rail. It’s a Schrader valve, like the one your tires.

Well, believe it or not the problem I was having just disappeared? I think there may have been water in my gas. Only time will tell but at least it buys me some time to pick up a fuel pressure tester.

Thanks for the suggestions! If the problem resurfaces I’ll get serious and tackle it then kinda FYI everyone since you were kind enough to help.

Happy Holidays Everyone….

my 1st guess... A tank of bad gas
2nd, maf problem

If it happens again, list your mods..

12-01-2005, 10:39 AM	#1 (permalink)
captnapi Junior Member Join Date: Nov 2005 Posts: 3	4.6 Engine Boggs Down over 3000 RPM 4.6 Engine Boggs over 3000 RPM 1997 GT 4.6 Automatic Trans Perfect idle – Starts perfectly – No engine light - Runs perfectly But… Over 3500 to 4000 RPM’s the engine just dies like it’s starving for gas. I changed the fuel filter and it helped ever so slightly but I still can’t push the engine over 4000 RPM. I don’t think this has anything to do with my problem but I also noticed the transmission refuses to shift when it bogs down @ 4000 RPM. I’m guessing when the engine boggs the vacuum insufficient to shift the transmission. Anyone ever experience something like this? If anyone that could point me in the right direction it would be greatly appreciated.

12-01-2005, 12:42 PM	#2 (permalink)
jeredan2003 Senior Member Join Date: Nov 2004 Location: Murfreesboro, TN Posts: 1,788	Doesnt really sound like a tranny problem to me. Could be your fuel pump. I had one go bad on mine and I have an 03. Go and find a fuel pressure tester. There should be a schrader valve on one of your fuel rails. Thats where the guage hooks up to. Hook it up with the car off then start the car after its hooked up. Look at the pressure while the car is at idle. Just follow the directions and you car should be at a constant 39-45psi. If its below that then you definately have a weak pump. __________________ 2003 DSG GT 5-speed Hellion 62mm and Flowmaster catback..... My bonestock 2v engine had been through 2 years of NX 100 shot, 3 years running 8-12lbs vortech s-trim, got into boost daily while racing on the weekends, had 157,000 miles on it, and was running like new

12-01-2005, 12:55 PM	#3 (permalink)
ponyexpress96 Senior Member Join Date: Jul 2005 Location: Concord, NC Posts: 113	yes i agree with the presure test always a good place to start but i also agree most likely the pump __________________ 96 GT Bassani X-Pipe Flowmasters Under drive pullies Hurst Short Shifter BBK Cold Air Intake(Fender)

12-03-2005, 06:10 PM	#5 (permalink)
ponyexpress96 Senior Member Join Date: Jul 2005 Location: Concord, NC Posts: 113	yea i would check at the rail and i dont konw if you can use ur compression tester to test the fuel rail when i dont it i used a fuel pressure gauge but that was all it was able to due but urs could diffrent cause snap-on has so much diffrent stuff Are you asking where ? if so there sould be a screw at the end of the fuel rail or a little thing in the end you can unscrew __________________ 96 GT Bassani X-Pipe Flowmasters Under drive pullies Hurst Short Shifter BBK Cold Air Intake(Fender)

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12-02-2005, 04:17 PM	#4 (permalink)
captnapi Junior Member Join Date: Nov 2005 Posts: 3	Thanks for the advice Fellas. It's really a 99 GT. confused it with my 97 Expedition. Are you referring to the injector’s pressure? Do I still check the fuel pressure on the fuel rail in the same spot and with the same pressure for a 99? Do you know the type and size fittings on the fuel rail? If at all possible, I want to use my Snap-On Compression tester with an adaptor. By chance do you know a part number I would need? Thanks for your suggestions…

12-04-2005, 05:22 PM	#6 (permalink)
captnapi Junior Member Join Date: Nov 2005 Posts: 3	I know I need a fuel pressure tester that was kinda a stupid question. I finally had a day off to look at the fuel rail. It’s a Schrader valve, like the one your tires. Well, believe it or not the problem I was having just disappeared? I think there may have been water in my gas. Only time will tell but at least it buys me some time to pick up a fuel pressure tester. Thanks for the suggestions! If the problem resurfaces I’ll get serious and tackle it then kinda FYI everyone since you were kind enough to help. Happy Holidays Everyone….

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