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Discussion Starter · #1 ·
Ok, so I have sniper special forces (plan on upgrading to commando, but haven't yet)

My question. In prep for centri blower, just installed Ford Racing 42lb injectors. Changed them in tune and long/short ft's don't look bad. Nothing else here changed wiht tune I was previously running without issue with my 24's as it was perfect! After changing in tune to reflect the 42lb injectors, I get an off idle "and only off idle" stumble when hitting throttle. If I go into throttle slowly I don't get hesitation. I was thinking the injectors aren't giving fuel quick enough, but any way to fix this without commando? Could it be too much timing all of the sudden, EGR? I did have the upper intake off to replace the injectors. Just running down the road it doesn't seem to miss or ...

Oh, btw it seems to idle around 22 degrees advance and bumps up if I roll on throttle slowly, but if I hit the gas quicker seems to retard as stumbles then jumps back up. I am not sure if this is a cause, or an effect of any fuel issues.
 

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What are the fuel trims? You need to take readings in steady state at different RPM ranges. Its most likely lean at the point in the MAF transfer function where it hesitates. You need a proper tune for the combo. You can't properly tune a car with the special forces software
 

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Discussion Starter · #3 ·
Just to let you know I tried something new. Prior to this I took one of my previous tunes and modified the injectors from 24 to 42 lb. No matter which tune it still hesitated. I started with base tune this time and no other changes besides 42 injectors and no more hesitation. My lt ft are averaging +2 in normal driving. My ST ft are hitting between +10 and -4

Not making any changes yet, but runs a lot better! Time to start logging!
 
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