Help me figure this out...

[9646GT]

Ive got a 96GT 5Speed and all I have added to it is an overpriced K&N cold air kit.. the inlet tube is plastic!! :-O Im getting a C&L aluminum one to replace. Also have a Jet Performance chip installed.

MY issue is.. when im driving and I accelerate to about 2500-3000 rpm I totally lose pull it just boggs out I can shift to a higher gear of course but I cant get past those rpm's.

Im suspecting one of my cats are clogged or bad because of the sound when I try to accelerate past 3000 rpm. This is definately a mind boggler. Is it possible my mass air flow is just flooding the exhaust with air it cant handle? Im getting hpipes and cat backs this week. Anyone have any input?

[Hammer]

Put the stock induction pieces back on and see what happens...

[9646GT]

going to give that a try.. ill report back soon

[9646GT]

Went back to stock... even took out the jet perfomance chip... Im still losing pull at around 3000rpm.. driving me nuts.... this damn car only has 26k miles on it.

Im not getting a check engine light so I cant have it hooked to a computer to see what it is. Does anyone know what could be causing me to lose pull. Im thinking this is in my exhaust...what else could it be? Help ..

I forgot to mention that Ive had the intake replaced after cracking the other and losing coolant. It ran fine after that. Also it has done this in the past as well it was just sporatic.. now its constant. im also gettting alot of heat in the center console coming from the exhaust...is this normal?

[cavdo]

had the same problem after i replaced my cracked intake manifold on my 98gt.

what my problem turned out to be was a inproper connected vacuum line.



first rev your engine and see exactly where and when it laggs. if it doesnt you might have a tranmission problem. dont get to any conclusions yet untill you

do the following things that might help:

- check vacuum lines(i dont know but on my 98gt, there is a little intake bypass line that has to be connected properly to the intake manifold otherwise the engine will not run correctly)

- check your MAF or MAS sensor & wires they might not be connected to the ECM properly

- check your belts, they "might" be busted, even after 26K miles

- check your alternator and battery.

- check your ECM, the chip you've installed could have messed up all the air/fuel mixture settings at specific RPM's

- check your intake tube, it might be jammed somehow(could be possible)

- check the engine timing

- check your exhaust, from headers to tips, you might have something big in there

*******do this only if the suggestions above did not help******

- check your fuel pump, fuel filter, and fuel injectors, they "might" be jammed

- check your intake manifold, it might be jammed as well

- check your ignition coils, ignition wires, and plugs they might not be firing properly, and you might be "running on 7 clilyinders" after 3000rpm, which hurts the timing. (that might cause the acceleration lag)

This should keep you busy for a while, and I Hope that the suggestions above will fix your problem.
dont forget that, you can do most of the things above in AUTO ZONE for free or minimal charge.

Let me know if you have any further questions.

P.S.: dont worry about the exhaust heat, its normal, mine gets little warm too after few hours of driving.

[9646GT]

first rev your engine and see exactly where and when it laggs. if it doesnt you might have a tranmission problem. dont get to any conclusions yet untill you

Ok.. I just had a reving session... at first it will rev fine but when I have it reved up and as its coming back down and I kinda punch it it boggs out at about 4000rpm... one side of my exhaust is crackling loud on its way back to idle.. kinda like a backfire. I had a really strong smell of phosphorus after a minute. I could actually rev the engine all the way to 6000rpms if I accelerated slowly. But like I said if I push to the floor quickly.. it boggs out completely.I was trying to simulate driving... punching it while its at 2000rpm. Now Im not really sure what this could be.

[9646GT]

I now supspect its my fuel pressure regulator.. going to do a pressure test on my fuel rails tomorrow. Hope thats all it is.. cause I just ordered a Mac Pro chamber H pipe and Mac cat backs and a C&L inlet tube

[blue00gt]

I had the same problem as you with my GT and it turned out to be damaged cats that melted and clogged up.

[9646GT]

well I dont think its my cats although it could be.. I had a pressure check on my fuel rail at idle it was 20 and giving it gas it went into 30's guy couldnt tell me if that was good or not.. I asked a guy I know that works for a ford dealer and he said it should be around 28. Im changing the fuel filter in it now cause I dont think its been changed ever.. we'll see.

[9646GT]

Well I changed the fuel filter.... it seemed to be the original. I noticed a big diff at first but my problem is not completely gone, its not nearly as bad as it was but there is still some pull loss. Ill have it scanned tomorrow and see what that tells us. Im guessing its the fuel pressure regulator.

Im having my Pro-chamber H pipes and Mac cat backs put on thursday. Cant wait to hear it after that.

[mlambrecht82]

It sounds like you might be having a missfire. When you open up the throttle plate the extra air that the engine sucks in raises the compression in the cylinder, this makes it harder for the spark plug to spark. Check your plug gaps, and make sure that none of the plugs are fouled. It might have nothing to do with the plugs and it might be some bad plug wires. Or if you have a multimeter you could check your coils for the proper resistance. Put one lead on one tower for a coil and the other lead on the other tower for the coil. I can't remember off the top of my head but the secondary resistance should be somewhere around 15,000 ohms. If its lower than that it is shorted and will not produce enough voltage to jump the gap at higher engine loads. The fuel pressure sounds a little low, but that wouldn't cause the problem, that doesn't mean that it doesn't have anything to do with your fuel system, a partially clogged injector could cause a lean missfire at higher rpms. If you can get an injector balance test done. Or just by a $2 bottle of STP and see if that fixes it. I doubt that will, but it won't hurt anything. To me it sounds like something to do with the ignition. Have someone look under the hood while you rev the car and cause the problem, have them look and listen to see if the spark is going through the plug wires, or jumping across the boot. If the plugs are gapped correctly and the wires are good, and the coils are strong then that should rule out the ignition almost entirely. The PCM could have a screwey knock sensor that is telling it to retard the timing at that certain rpm where the engine has that certain vibration.
I hope this helps.

[9646GT]

Thanks im definately going to check out my plugs for sure.. im using autolites in there now.. I was just told I need to run motocraft fromt he dealer.. is this true? I changed these right after I got the car.. which was only a 2 months ago.

[9646GT]

Well ...the problem is a bad fuel pump which isnt suprising. Good thing a shoppwner owes me a favor. Question is .. I know there is aftermarket fuel pumps out there was wondering if it would be a good idea to go that route.

[Mustang92]

Just to touch on something in your original post the plastic tubing from the K&N set up is better than any metal tubing. Plastic does not transfer or absorb heat as much as aluminum or steel so your incoming air doesn't get heated like it would with say a MAC CAI set up. The cooler the better so I'd actually say keep the plastic piping it's your best option.

Bill

[Badass_yellowGT]

at idle the pressure should be a minimum of 20 psi take the vacum hose off it should be about 40 psi if it`s in this range your good. sounds like a bad coil to me.

[9646GT]

Originally posted by Badass_yellowGT
at idle the pressure should be a minimum of 20 psi take the vacum hose off it should be about 40 psi if it`s in this range your good. sounds like a bad coil to me.

By bad coil do you mean the things the spark plug wires stem from in front of the engine... ? Are they called ignition coils.. and How would I check them?

[9646GT]

well I tested the coils ..

Primary resistance spec- 0.3 to 1.0 ohms (Actual tested 1.2-1.6 on both coils)

Secondary resitance Spec- 6.5 to 11.5K-ohm (Actual tested 14.38K-ohms on both coils.)

Are these too far outta spec and need replaced? I replaced the Spark plug wires. It still Boggs out when I try to accelerate above 3-4000rpms. I just find it highly unlikely that both are reading the same and they are bad.

[9646GT]

Replaced the fuel pump in her today.. that did the trick.. the car sat too long before I got it.. gotta replace the tank too got some rust going on in there.... cant wait to see what that will cost.