hey guys, i recently had a cyl misfire. my mechanic did all types of tests and figured out it was because of the dirty injectors, he cleaned them, throttle body, pistons, intake. no misfire. but when i brought the car home, i realized my car had a delayed start up or like a little hesitation. it was only sometimes, not all the time. maybe when it was cold? my mechanic said the ecu prob needs to be recalibrated. is this right? i never had this issue before.

 

Need a little more information on the car? Parts? Tune? ECU? etc....

 

no the car is stock no tune

 

Your problem is likely hardware.

 

wdym by hardware

 

It's not the ECU or tune. You're probably looking at a fueling issue. I'd probably start with the pump and regulator if the injectors have already been cleaned.

 

Grasping at straws: Wait until the fuel pump stops running before hitting the Start button. This will ensure there's full fuel pressure in the system. Only takes a couple of seconds.

-- Chuck

 

To start fresh after all of the work your mechanic had completed I highly recommend resetting your long-term (important ones for start) and short-term fuel trims aka reset your ECU by pulling appropriate fuse or by disconnecting your car battery negative terminal for a minute, or just play it safe and do 10 minutes.

Your STFT and LTFT (fuel trims), if they were pegged at an extreme due to mechanical issues that you mechanic had solved, would be set back to the norm after reset and you’d start fresh.

Report back if that solved the issue.

 

Cranking is time based, LTFT have zero interaction here.