Hello everybody. I have an issue I can't figure out. I have an 89 foxbody with edelbrock heads. F303 cam. Cobra intake. Shorty headers. It'll crank and drive fine. After about 20 minutes of driving and sitting at red-light it will seem like something kicks on and the idle gets super rough. Doesn't seem to affect during driving though, but it will idle bad enough to where it will sometimes die.
Idle issue when hot
- Thread starter Csheets88
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- Mar 2, 2015
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Intake air temperature sensor. Seems like it may be your issue....or the coolant temperature sensor. Not the one that looks like a little stud but either the one in the coolant bypass pipe or the one that screws in the intake under the upper intake on drivers side. If the sensors are disconnected or not working it will make the computer think the car is still cold.
Even if the CEL (check engine light) is not on there can be codes. This is due to only emissions related codes setting the CEL. I would pull codes first then go from there.
mikestang63
SN Certified Technician
Check the ground wire that's bolted to the back of the left (drivers side) head and goes to the fire wall.
Does the alternator charge sufficiently at idle? Needs 13.5 volts or close to at idle.
Does the alternator charge sufficiently at idle? Needs 13.5 volts or close to at idle.
These are not answers that help, the volts will very according to RPMs normally, need to get familiar with diagnostic tools and terms, beg or borrow a volt/olm meter, read voltage at idle, nothing on, and then with blower, lights and wipers on, then say 1800 RPMs, and battery voltage with engine/key off. I have to write things down cause my memory bank is mostly full of useless crap that takes up too much space.
Also need to monitor fuel pressure to see if/what changes when it starts to act up.
We can point you in the right direction, a good start would be a repair manual or better yet an assembly/repair manual by Ford, ebay has some.
Some helpful info can be found in on the tech main page:
Technical Thread/how-to Index
Guys, if "that should be a sticky," then please reply to this thread with the link to your suggestion and why you think it should be added. How to determine if a thread should be included: - Does the topic address a common fox 5.0 owner's needs? / Is it a frequently asked question? / Is it...
stangnet.com
The thingy on the distributor is the TFI. Did you get the proper one for your car/transmission? Auto car takes a different one than standard.
To stop the idle drop when there’s a load (lights or heater blower) get a 130 amp alternator kit.
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