idle problem

90 GT

New Member

Apr 13, 2004

12

0

0

Jul 21, 2004

#1

• Jul 21, 2004

• #1

i own a 1990 gt and have a problem with it idleing steady.the gt basically for now has mac long tube headers and 373 gears in the back.i just gave it a fresh tuneup (plugs wires distributor cap and rotor).i tried adjusting the throttle screw and i brought the idle up to 1000.like a few days after the revs dropped to about 600 and it goes up 800 and back down again ,i have no idea what would cause it to do that.any help out there i'd really appreciate it. thanks

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

31,179

33

129

Jul 22, 2004

#2

• Jul 22, 2004

• #2

the computer will adapt. so if you manually raise the idle, it will eventually figure it out and try to get it back down to stock idle specs. because things are out of whack, it can cause surging and other issues.

some have disconnected the IAC - i have not and dont know how effective that is.

just some info. good luck.

 

blackstangt

Member

May 31, 2004

460

1

19

ny

Jul 22, 2004

#3

• Jul 22, 2004

• #3

it's not supposed to be at 1000 at idle. The computer is adjusting to get back down to 650-700 rpm which is the comp set idle. Also, try disconnecting the neg for 15 mins, and set the idle to 700.

 

gungfusemaj

Member

Dec 13, 2003

211

0

16

Bradenton Fl

Jul 22, 2004

#4

• Jul 22, 2004

• #4

Black is right 700 Rpms make sure your TB sensor is set at the right voltage.

 

B

bsedwebt70-5.0

New Member

Jul 1, 2004

320

0

0

Charlottesville, VA

Jul 22, 2004

#5

• Jul 22, 2004

• #5

clean your tps - take off your air intake tube that goes to the throttle body and go to town - you will find if you pull off that little 2 bolt on thing at frt of the throttle body area that allows the gas to return (EGR) it will be coated in carbon inside - take it off and clean with carb cleaner - works every time - takes about 10 minutes with an old toothbrush and rags - I wish I knew better how to describe it

 

ironmedic

New Member

Mar 18, 2003

1,361

0

0

Puyallup, WA

Jul 22, 2004

#6

• Jul 22, 2004

• #6

also check your TPS voltage!

 

88_GT_5_oh

Sportin' a turbo 5.0 in Canadistan

Jul 4, 2004

1

0

1

WPG/MB/CA

Jul 22, 2004

#7

• Jul 22, 2004

• #7

try this.. it worked for me when i had this problem

http://www.fordmuscle.com/archives/2002/01/tenpin/index.shtml

 

90 GT

New Member

Apr 13, 2004

12

0

0

Jul 22, 2004

#8

• Jul 22, 2004

• #8

guys thanks alot for the help.i still have a problem with the tps sensor reading at 1.1 instead of it being in the .98 .99 range.i cant get it to go any lower than 1.1 and i don't know what to do next.

 

$uperstang

New Member

Jul 20, 2004

476

1

0

Detroit, MI

Jul 22, 2004

#9

• Jul 22, 2004

• #9

I had the same problem with mine. If your car is surging at stop lights (funny idle) just replace the TPS all in all and you'll be fine.

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

31,179

33

129

Jul 22, 2004

#10

• Jul 22, 2004

• #10

90 GT said:

guys thanks alot for the help.i still have a problem with the tps sensor reading at 1.1 instead of it being in the .98 .99 range.i cant get it to go any lower than 1.1 and i don't know what to do next.

Click to expand...

IIRC, the puter zeroes the TPS reading out at start up, each time. as long as the static reading is ~1.30 volts or less, it is immaterial (per Michael and Stang & 2 Birds).

that said, some have diminished surging and such, by dialing the static TPS reading down from slightly over 1 volt to below.

good luck.