Quick Question

[JStang98]

Ever since i bought my 98 GT the gas guage only half a** works, when i fill it up the guage will show full but after about 30 or so miles it will drop down to rite under 1/2 tank and stays there its never gone lower and i was wondering what could cause this cause its starting to bug me pretty bad, and also do you think a leaking egr valve could be the culprit to high idling problems?

 

[BrandoGT]

I have no idea for the fuel gauge issues. I guess i would say describe your high idle issues because i thought mine had high idle issues because when it started it would run high idle but after a couple of minutes of running it the car idles down to about 750 rpm.

 

[JStang98]

Alright the high idle problems are like this i got a 98 mustang gt recently its started idiling weird if i dont drive it for a day or so when i start it it will idle around 2 thsnd rpm or sometimes higher for a couple min and sometimes it dont stop, and when i drive it when its doing this it seems to have all the hp there it just idils way to high but after just a couple min it will idle back down to normal and when it does it seems like i have a big drop in hp. I cant seem to figure this out.

 

[MustangChris]

high idle is probably the IAC.
the broke gauge is probably a bad float in the tank (i would guess. ive honestly never taken it out or apart.)

The problem with the guage is to fix it you are *probably* going to have to drop the tank. the gauge is electrical, so its like, 2 wires going back to the tank... so one solution (the cheep and easy one) is to buy an aftermarket gauge (i suggest autometer) and plug it in... that will tell you if its a bad gauge for a weekend of work and $50.

The next step would involve dropping the tank.


As for the idle problem, i suggest taking the vacuum line off the front of the throttle body... spray MAF Cleaner into it and rev it up a little. do this process a few times.

Let us know if that helps.

 

[glittle75]

for the guage, you can try an aftermarket gauge first as stated, if that dont work, you need to drop the tank down, get the fuel level sending unit thing out and see if its broke / worn / sticking, etc..

also, have you ever run it way low on fuel? like the gauge shows half tank, but you know from mileage you need to fill up? if so how many gallons did it take, you have a 15 gallon tank, and you should be close to that.

this may sound wierd, but i saw on TV where a guy was having the exact same issue, he chased the issue for a while, finally dropped the tank, looked inside, and there was a few pounds of drugs inside it. someone was using the tank to run drugs, and the guage never went low because of the displacement of the stuff inside. just a thought.

guy turned the drugs in to the cops and didnt get any charges whatsoever though

 

[MustangChris]

i must have gotten some of those... gas laced weed will grow hair on your palms...

 

[JStang98]

Yeah ive ran it completely out of gas a couple times thats how i found out it wasnt working but yeah now i fill up on mileage but normaly it will only hold aroumd 25$ or somewhere between 7 to 10 gallons because i try not to run it to low cause ive never been able to figure up gas mileage so i never know how much gas i got left. And yeah if my gas tank was full of drugs id just sell it all and finally get those heads ive been wanting lol jk. And the idiling problems tmro ill try some of those suggestions and let yall know what happens. Thanks

 

[MustangChris]

my car goes 300 miles on a full tank.

 

[stanger]

Hey Chris, I only get 250 miles from a tank what have you done to add mileage?

 

[JStang98]

Alright guess ill fill it up and run it till its dry i guess.

 

[MustangChris]

Hey Chris, I only get 250 miles from a tank what have you done to add mileage?

When I purchased the car it had the following modifications:
Mac cold air intake + Filter
FRPP Ceramic Coated Shorty Headers
Bassani Catted x-pipe
Flowmasters
Center line 16" wheels
3.55:1 Gears
Chrome Strut tower
Unknown brand of Piggyback Underdrive pulleys
FRPP Aluminum Driveshaft (some say it may have come stock)

Things I've added:
Steeda Underdrive pulleys
Steeda Idler Pulleys
Gatorback Belt
BBK Chrome Valve Covers
FRPP 03/04 Cobra Front Control Arms
BBK Standard Rate Gripp Springs
Tokico Shocks and struts
Maximum Motorsports Caster Camber Chrome plates
Drilled and Slotted front rotors
1999 SVT Cobra Steering Rack
Maximum Motor Sports solid motor mounts
Maximum motor sports bump steer kit
Prothayne Sway bar end links
Prothayne Bushings all around
Prothyane Spring isolators
Maximum motor sports Solid Steering Shaft
Spec Stage 2 Clutch (stock flywheel)
FRPP Heavy Duty Clutch fork
FRPP Heavy Duty Throw Out Bearing
Hurst Short Throw Shifter + White 5 spd. knob
Roush Shifter Boot
Lakewood Universal Joints
Jegs Driveshaft Safety Loop
Moser 31 spline Axles
Eaton LSD Posi Diffy
SVO 4.10:1 Gears
FRPP Rear axle Girdle
Yokohama 520 Tires
Maximum Motorsports Black Powdercoated Full Length Weld-in Sub-Frame Connectors
Steeda Ajustable Clutch Cable
Steeda Adjustable Quadrant
BBK Firewall Clutch adjuster


i get close to 320 per tank.

 

[Willis_98GT]

im lucky if i get 240