Weird 3.1 Hesitation... can't figure it out!

[toadson]

re

I got the chip back a few days ago. He adjusted the fuel tip in, and it seems to run perfect when cold. The car revs quicker, takes off much easier and was perfect between shifts. However, once the car warmed up, the hesitation returned. Im probably going to ship the chip back, as he suggested adding more fuel during the tip in. It sucks having to ship the chip off any time I need adjustments, but its free of charge (minus $1.30 for shipping). I'll let you know how it turns out.

[3XTurboAgain]

Could it be your idle air control?

[toadson]

re

Thats what I was thinking too, but I manually did an IAC relearn with a scanner and got the IAC in its right specs, and it still had the hesitation. Ive also switched out 3 other IACs to no avail.

[LZeppelin513]

I am also working with Ryan. I figured it wouldnt be a perfect tune the first try so when i was at the junkyard last time i found a car that would have the 7730 computer and pocketed the chip. instead of having to wait around if i need to send him my chip i can just send the spare and still drive on the old tune.

[torq455]

mine did the same thing too. it's a common flaw. i've had a few of the 3.1 MPFI's in and they all have done it. had to try to see if it was just my car. after putting a 62mm TB on and screwing the idle adjustment screw open more, that hesitation is gone! it was sooo annoying! i found the further i opened the throttle plate up the less that bog was there. i have it opened as far as i can now so that my IAC count reaches 1-2 steps fully hot and no load of any kind at idle.

[toadson]

re

Interesting... I have tried messing with the idle screw as well, but I didn't adjust it a whole lot. It didn't seem to help the hesitation any though. From what I'm told, you are supposed to keep the IAC counts around 14-20 at idle, but I guess if it cures your hesitation, who cares? I wouldn't mind looking into the larger throttle body. Where did you get yours from? Also, is your car a 5 speed? I wouldn't think you would notice the hesitation as much in an automatic. As far as the extra chip idea, I would have gladly done that last time I was at the junkyard, but completely forgot about it.