Alright I’ve been searching and searching for months to a solution to this problem. I installed a short ram intake on my 3.5 TL and it started shifting super rough and it specifically has one downshift when accelerating from 20-30 mph and it hesitates for a couple seconds and then shifts super hard. It almost feels like a slip but the transmission shifts perfectly fine in manual mode. I have been told I need a tune so I got a Ktuner and the base map helped a little but didn’t fix it still. Now i have concluded from multiple sources that I need a custom tune but the best price I’ve been able to get is $650 which honestly I don’t feel like putting that much money into this car (it has 185,000 miles). Is there any other less costly solution for me out there?

 

Did you just reset your ECU by removing the battery cable for 10 minutes and letting the idle re-learn? I would have gone that option before getting a KTuner for just a SRI.. .

 

Yeah, I did try that, made no difference. I have read the other thread on here with the guy with a similar problem and tried everything from that thread. I’ve done multiple different types of resets none worked.

 

Does it really need a custom tune? The stock ktune profile for SRI/Intake should work. I did j-pipe and SRI and used the stock map. I did these mods at around 50k miles and honestly the KTuner itself is fully worth it for the increased responsiveness to the shifting. The car feels like a new car when I applied one of those tunes.

 

bolt ons like intake shouldn't need a tune. what diameter is the pipe where the maf sits.