idle problems

9

91_4ourBanger

New Member

Feb 8, 2004

255

0

0

Mar 16, 2004

#1

• Mar 16, 2004

• #1

my 91 automatic stang is idling really roughly. in a driving gear it will idle at 1000rpms, but then suddenly drop to 700-800 rpms for a slight second and the lights will dim and the car will shake like it wants to shut off, then the rpms will go back up, but this doesnt happen in nuetral. anyone know any ideas as to what the problem is???/

 

9

91_4ourBanger

New Member

Feb 8, 2004

255

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0

Mar 16, 2004

#2

• Mar 16, 2004

• #2

i think it might be my spark plugs, but id like a 2nd 3rd and 4th opinions

 

i4power

Founding Member

Jan 11, 2002

1,083

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0

Eglin AFB, Florida

Mar 17, 2004

#3

• Mar 17, 2004

• #3

Do the major tune-ups first, then check out your transmission. The A4LD automatic is a big steaming chunk of crap, and could be failing.

 

9

91_4ourBanger

New Member

Feb 8, 2004

255

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0

Mar 17, 2004

#4

• Mar 17, 2004

• #4

i4power said:

Do the major tune-ups first, then check out your transmission. The A4LD automatic is a big steaming chunk of crap, and could be failing.

Click to expand...

the transmission is brand new though...

 

Jquintel

Member

Jun 8, 2003

194

0

16

Fort Wayne, IN

Mar 17, 2004

#5

• Mar 17, 2004

• #5

91_4ourBanger said:

i think it might be my spark plugs, but id like a 2nd 3rd and 4th opinions

Click to expand...

I'll second that... my 93 used to idle rough, did a tune up, idles fine now

 

K

ka0tyk

Founding Member

Oct 10, 2001

1,610

0

0

Los Angeles, CA

Mar 17, 2004

#6

• Mar 17, 2004

• #6

CLEAN IAC

CHECK TPS VOLTAGE AT IDLE TO BE SET AT .98 VOLTS

CHECK PLUGS

CHECK WIRES

RUN CODES

CLEAN EGR

if still runs crappy move onto bigger things

CHECK O2 SENSOR

CHECK MAF/MAP SENSOR

CLEAN INJECTORS

 

T

Tru_Blue_104

New Member

Nov 13, 2003

218

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0

MN

Mar 18, 2004

#7

• Mar 18, 2004

• #7

by clean injectors, do you mean just run some fuel stuff? or are you talking about taking them out and doing it the right way? just curious cause I've done everything on that list.

 

K

ka0tyk

Founding Member

Oct 10, 2001

1,610

0

0

Los Angeles, CA

Mar 18, 2004

#8

• Mar 18, 2004

• #8

to correctly set idle:

unhook positive battery terminal for at least 30 minutes

unplug IAC solenoid

turn idle set screw a couple times to raise idle

put positive battery back on

start car

turn idle set screw down until idle is at about 800 rpms

turn off car

set TPS sensor to .98 volts

plug in IAC solenoid

start car

turn on all accessories and drive for a while


this sets your base idle, and then the IAC can open to keep the car from stalling when accessories slow idle down... sometimes you can make a small change to the idle and then the IAC has to do more work than its supposed to, resulting in a stumbling idle.