Help RPM's Drop slow and NOT Vacuum Leak?
 

Hey guys I have a Evo IX and after I got my tune done my RPM's drop crazy slow from a hard pull. Takes like 10 seconds to drop from red line. I only noticed it after tuning the car on E85. I have basic bolt on mods. We did a vacuum leak test and replaced the TB shaft seals. And it still does it. What else could cause this? Any help would be great. Thanks guys.

Have you thought about going back to the 'tuner' and asking him what the deal is? Probably tune related if it wasn't doing it before your tune. If your tuner helped you with your TB seals and vacuum leak test (do you mean boost leak test? If not have you done a boost leak test?) and is clueless as to what's going on...you may want a new research a new tuner.

We did a Vacuum test and a boost test. Car got tuned with the vac leak, could that have to do with it?

Maybe this will help ya out

https://www.evolutionm.net/forums/ev...hang-tune.html

&

https://www.evolutionm.net/forums/ec...per-table.html

Is the throttle body flap hanging up?

The car only seems to do it after a hard pull to red line or higher RPM's above 5k. I checked the throttle cable and the TB it's self. Both seem to be fine and operate smoothly.

After a hard pull my Air/Fuel wont go to zero (or flat line) like if I let off the gas on the highway. Not sure if my car is just dumping so much fuel that it takes forever to burn off?

I also ordered the Mil Spec TB and should have it in this weekend. Hopefully that might have something to do with it?

Put in the new TB and still no changes. Anyone have any ideas?

If it was the tune how could I figure that out?

Its normal. Does it stock, does it after a tune.

Is it normal that it happens all the time or only here and there after WOT?

Bet its the idle air control valve settings...search "Evo rev hang"

Hey I looked into this and passed it on to my tuner. I hope this fixes my issues I don't enjoy driving my car this way! Thanks X..

NP, let me know if that fixes it. I've been messing with mine for awhile to try to smoothen the car out some, its better than it was but it still doesn't feel like it should