I know modified 5.0s are no stranger to idle problems. I’ve read many of the threads and search everything I can think of. So I’m down to making my own post. So here is goes: I have a highly moded 5.0 in a 65 mustang. I build the motor from scratch I started with nothing. The highlights are e303 cam, Trickflow heads, fuel rails, 30lbs injectors, throttle body, BBK MAF, stock computer with a Motes chip custom tune, and an Innovative wideband.
Problem: Motor runs great mid and top end.
After warming up the idle has a “stutter” it seems a lot like a miss but if it is I can’t find it. It will idle around 900/1000rpm then stumble and drop to 500/600rpm. When it does the wideband goes from 15:1 to 20:1 but smells rich. Problem gets worse in gear and way worse with ac on. When you put your foot in it if the idle is good the car is a beast, if the idle is at a stumble it falls on its face until mid range then lights the tires up. And it had no codes other then neutral switch which is not hooked up and speed sensor which is also not hooked up.
I have checked:
For a miss
For a vac leak
Check TPS voltage
Fuel pressure
Timing
I’ve swapped O2 sensors
MAP or BAP as it’s used
I sent the MAF off to be re calibrated
I added the LMR throttle body spacer
None of these have changed the issue. What ideas to you have? I’m down to thinking I have a computer issue. I’ve bought a Magasquirt plug and play but haven’t made the leap.
Problem: Motor runs great mid and top end.
After warming up the idle has a “stutter” it seems a lot like a miss but if it is I can’t find it. It will idle around 900/1000rpm then stumble and drop to 500/600rpm. When it does the wideband goes from 15:1 to 20:1 but smells rich. Problem gets worse in gear and way worse with ac on. When you put your foot in it if the idle is good the car is a beast, if the idle is at a stumble it falls on its face until mid range then lights the tires up. And it had no codes other then neutral switch which is not hooked up and speed sensor which is also not hooked up.
I have checked:
For a miss
For a vac leak
Check TPS voltage
Fuel pressure
Timing
I’ve swapped O2 sensors
MAP or BAP as it’s used
I sent the MAF off to be re calibrated
I added the LMR throttle body spacer
None of these have changed the issue. What ideas to you have? I’m down to thinking I have a computer issue. I’ve bought a Magasquirt plug and play but haven’t made the leap.
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