missing at light throttle in park

[blackgn1]

Is it normal for a engine to miss in park at light throttle? After starting a new tune i have just noticed it. Idles fine. 206/206 roller. As the rpm's come up the miss follows. The coil/module has been checked via Richard Clark's Caspers coil tester. SD chip so there is no maf sensor. Scanmaster numbers are perfect except for AF number dipping to 4.

 

[blackgn1]

I will be replacing the coil/module with new Delco parts but something else is going on i feel sure. Checking grounds next. Then vacuum lines again for the tenth time.

 

[kidglok]

if its chip related, try to run it in closed loop for low throttle and idle (set parameter 7 to and even number). also add some a/e fuel (param 20) not sure if it will help cause it happens in park, but its worth a shot...if it stops when using c/l check the cc to see correction (afr correction on powerlogger if you updated it) and adjust the tune accordingly. good luck- james

 

[kidglok]

btw- i may need another set of those wires

 

[TurboBob]

my car has always sorta done that. How much of a miss? occaisional+random or a dropped cylinder?

B

 

[KL Mallender]

Possible EGR valve ?


Kevin.

 

[lost2a6]

I would bet that it's lean.

 

[blackgn1]

It could be lean. I adjusted the chip to run around 13.5 AF at idle on the wideband. It has always idled pig rich until the SD chip really cleaned that issue up. If you hold the throttle open up to around 1500rpm the miss is constant. It's also the same at around 2000rpm. Driving it will miss every 5 miles or so just once. It very well could be this engines nature. That's what makes this a mystery fix. The car runs good. Needs a converter to do any real tuning and the weather here has turned cold. Just able to do garage tuning. The track logs have all been knock free runs. Little knock on the shift but that's it. AF around 10.5-10.8. The EGR has been removed.

 

[blackgn1]

lost2a6 is most likely going to be right. She's lean at idle. I can spray a little alky with the test button and it clears up. My Wideband O2 sensor has taken a dump.