so guys i bought this 5.0 off my buddy and it came with bigger MAF ported upper lower intake and ported heads.. trickflow stage 2 cam.. shorty headers stock h pipe stock mufflers. car will idle at 1000-1500 rpm and come down to 800rpm after a minute or twi.. if i tap the gas pedal it will rev up to 1500 again when it should barely go over 1000 considering i barely tap the gas.. will stay at 1500 rpm then come back down.. any idea what it can be?? also valves sound like theyre ticking i know its a typical foxbody problem but its pretty loud.. valve adjustment?? maybe dirty valves or clogged valves? please help a foxbuddy here thank you guys!!
High Idle On 1990 Notchback 5.0 Help!!
- Thread starter BAKENBACON
- Start date
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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. It includes how to dump the computer codes quickly and simply as one of the first steps. 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 200,000 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 200,000 hits, which indicates it does help fix idle problems quickly and inexpensively.
Dump codes plus basic idle reset procedure.
We also need more info on what this car is. 86-88 speed density? Or a mass air car?
We also need more info on what this car is. 86-88 speed density? Or a mass air car?
You don't just 'turn the idle down' at the throadel body, there is a procedure you have to follow.
etting the base idle speed:
First of all, the idle needs to be adjusted to where the speed is at or below 600 RPM with the IAC disconnected. If you have a wild cam, you may have to raise this figure 100-150 RPM or so.Then the electrical signal through the IAC can vary the airflow through it under computer control. Remember that the IAC can only add air to increase the base idle speed set by the mechanical adjustment. The 600 RPM base idle speed is what you have after the mechanical adjustment. The IAC increases that speed by supplying more air under computer control to raise the RPM’s to 650-725 RPM’s. This figure will increase if you have a wild cam, and may end up between 800-950 RPM
Remember that changing the mechanical idle speed adjustment changes the TPS setting too.
Thanks to jrichker for this
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