Hey all, I'm new to this forum & new to mustangs honestly, been part of the Thirdgen world for awhile & decided to go a different route....anyway I bought a 1990 lx coupe 5.0 aod car....I bought it knowing itd be a project....so let's get started on my problems.....first off....at WOT the trans won't shift out of first....it just bounces off 4800-5000...but shift fine at any other time...shifts really hard too.......second...the air bag has been deployed...but the car is straight & even the original hood is perfect...so where are the sensors that actually deploy the bag? & where do you get an airbag, & wheel & how do you get the air bag light to atop blinking after that.....last....the car won't idle on a cold start...I have to hold it at 1000-1500 for about 3 minutes then she will idle but even then the idle kind of bounces between 600-800...I've only replaced the TPS & MAF car has bbk headers, trickflow upper & lower intake and a cai...that's it.
New Project, New Problems, New Questions
- Thread starter lee300
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perform a base idle reset to fix your surge/idle issues:
Summarized/Corrected Base Idle Reset version
1. Clean TB with carb cleaner and nylon brush (toothbrush size). Engine off, fully open TB blade and spray/brush TB until all gunk and oil residue is cleaned.
2. Allow to dry, or close TB blade and start engine until it clears all carb cleaner fumes/liquid.
3. Let engine idle...if it doesn't, increase idle speed via TB stop screw until engine stays idling on its own.
4. Disconnect IAC valve, if engine dies repeat 3 with IAC disconnected.
5. Set idle speed to the lowest setting possible between 600-800 rpms with IAC disconnected. It is key to use the lowest possible to prevent idle surge, rolling, etc once the IAC is connected as follows.
6. Turn engine off, and reconnect IAC
7. With Ign On Eng Off, check TPS voltage output....if it's between .7vdc - 1.0vdc, it's OK. This voltage check should be done between the Green and Black wires at the TPS side connector as shown in the pic below....(-) terminal of the DVOM on the Black wire and (+) terminal on theGreen wire.
8. Disconnect battery (-) for 3-5 minutes.
9. Reconnect battery, start engine, allow it to idle for 2-4 minutes to confirm setup,
10. If idle speed falls too low or stalls, increase idle speed via the TB set screw a little at a time.
11. Turn engine off for 20 seconds, re-start engine and repeat 9 - 11 if required.
12. Reconfirm TPS output is within the .7vdc - 1.0vdc range.......you're done!...
View attachment 108085 ..no need to reset ECM KAM (reset computer) b/c the TPS minimum value used for idle control, is automatically reset by the EEC-IV every time the ign is cycled on-off for 20 seconds-on, and as explained in the next post
13. Allow a 10-20 minute "relearning" period under normal driving conditions (drive cycle).....now you're done.
Summarized/Corrected Base Idle Reset version
1. Clean TB with carb cleaner and nylon brush (toothbrush size). Engine off, fully open TB blade and spray/brush TB until all gunk and oil residue is cleaned.
2. Allow to dry, or close TB blade and start engine until it clears all carb cleaner fumes/liquid.
3. Let engine idle...if it doesn't, increase idle speed via TB stop screw until engine stays idling on its own.
4. Disconnect IAC valve, if engine dies repeat 3 with IAC disconnected.
5. Set idle speed to the lowest setting possible between 600-800 rpms with IAC disconnected. It is key to use the lowest possible to prevent idle surge, rolling, etc once the IAC is connected as follows.
6. Turn engine off, and reconnect IAC
7. With Ign On Eng Off, check TPS voltage output....if it's between .7vdc - 1.0vdc, it's OK. This voltage check should be done between the Green and Black wires at the TPS side connector as shown in the pic below....(-) terminal of the DVOM on the Black wire and (+) terminal on theGreen wire.
8. Disconnect battery (-) for 3-5 minutes.
9. Reconnect battery, start engine, allow it to idle for 2-4 minutes to confirm setup,
10. If idle speed falls too low or stalls, increase idle speed via the TB set screw a little at a time.
11. Turn engine off for 20 seconds, re-start engine and repeat 9 - 11 if required.
12. Reconfirm TPS output is within the .7vdc - 1.0vdc range.......you're done!...
View attachment 108085 ..no need to reset ECM KAM (reset computer) b/c the TPS minimum value used for idle control, is automatically reset by the EEC-IV every time the ign is cycled on-off for 20 seconds-on, and as explained in the next post
13. Allow a 10-20 minute "relearning" period under normal driving conditions (drive cycle).....now you're done.
You guys with idle/stall problems could save a lot of time chasing your tails if you would go through the Surging Idle Checklist. Over 50 different people contributed information to it. The first two posts have all the fixes, and steps through the how to find and fix your idle problems without spending a lot of time and money. I continue to update it as more people post fixes or ask questions. You can post questions to that sticky and have your name and idle problem recognized. The guys with original problems and fixes get their posts added to the main fix. 
It's free, I don't get anything for the use of it except knowing I helped a fellow Mustang enthusiast with his car. At last check, it had more than 159,000 hits, which indicates it does help fix idle problems quickly and inexpensively.
It's free, I don't get anything for the use of it except knowing I helped a fellow Mustang enthusiast with his car. At last check, it had more than 159,000 hits, which indicates it does help fix idle problems quickly and inexpensively.
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