Random misfire? Jerk/Rpm drop - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

Rem0v3r · 02-26-2019, 04:36 PM

I've had an issue with my 2013 l99 for a while now and haven't been able to figure it out..

What happens:- the car will feel as though the brakes are being touched for a split second the car will feel as though it's freewheeling, then the engine speed will catch up to the transmission speed really quick and the entire vehicle jerks... all this happens in less than a half second. Some times are more severe than others.

It usually happens within 30 seconds of a wide open throttle pull. It doesn't usually happen during the WOT pull, and it can happen even if I don't go into WOT.
The severity of the "jerk" seems loosely related to how hard I get on it at WOT.

This happened even when stock. The car is now boosted and has new injectors, fuel pump and I've changed plugs and wires twice. (Did help a little).

Using hp tuners, I see that the "blip" does reduce engine rpm momentarily by around 200rpm, dynamic airflow numbers spike high, fuel pressure drops (I believe this is normal for the e38), mass airflow numbers don't change (car is speed density tuned and doesn't use the maf), the wide band will read rich directly after the event.. injector duty cycle will also increase during the event..

Educated suggestions are appreciated

zlathim · 03-01-2019, 11:21 AM

Have you tried asking this question on the HPTuners forum?

Rem0v3r · 03-01-2019, 05:35 PM

Just posted one over there

02-26-2019, 04:36 PM	#1
Rem0v3r Drives: 2013 ss2 vert l99 Join Date: Apr 2017 Location: South florida Posts: 150	Random misfire? Jerk/Rpm drop I've had an issue with my 2013 l99 for a while now and haven't been able to figure it out.. What happens:- the car will feel as though the brakes are being touched for a split second the car will feel as though it's freewheeling, then the engine speed will catch up to the transmission speed really quick and the entire vehicle jerks... all this happens in less than a half second. Some times are more severe than others. It usually happens within 30 seconds of a wide open throttle pull. It doesn't usually happen during the WOT pull, and it can happen even if I don't go into WOT. The severity of the "jerk" seems loosely related to how hard I get on it at WOT. This happened even when stock. The car is now boosted and has new injectors, fuel pump and I've changed plugs and wires twice. (Did help a little). Using hp tuners, I see that the "blip" does reduce engine rpm momentarily by around 200rpm, dynamic airflow numbers spike high, fuel pressure drops (I believe this is normal for the e38), mass airflow numbers don't change (car is speed density tuned and doesn't use the maf), the wide band will read rich directly after the event.. injector duty cycle will also increase during the event.. Educated suggestions are appreciated

03-01-2019, 11:21 AM	#2
zlathim Drives: 2010 Camaro 2SS/RS M6 Join Date: May 2009 Location: Idaho Posts: 726	Have you tried asking this question on the HPTuners forum? __________________ GPI SS2; EE E2 catch can; SP 1 7/8" LT Headers w/ hfc; FM AT 3" cat-back; CAI Cold Air Intake; AEM Wideband Tuned by GPI McCleod RXT; MGW flat stick; Ram Clutch slave cylinder & hydraulic adjuster BMR cradle & diff bushings, trailing arms, toe rods & upper control arm bushings Hotchkis sub-frame brace Stop Tech Z-23 brakes 4.10 gears, Eaton Truetrac, LPW diff cover Best 1/4 mile 12.073 @ 115.68 mph 3,300 ft DA

03-01-2019, 05:35 PM	#3
Rem0v3r Drives: 2013 ss2 vert l99 Join Date: Apr 2017 Location: South florida Posts: 150	Just posted one over there