jschick

I have a issue which happens every now and then on my 99 2.8, maybe once every 300-400 miles. the car runs great, but the car will start to idle very rough then the CEL comes on (yes generally this happens when the car is fairly cold, first 10-15 minutes of startup) the idle will always stabilize almost right after the CEL comes on. I get code 16795 for secondary air pump incorrect flow detected. I have gone thru the Vac lines and the pump is working. My guess is one Combi valve may be sticking, but will this cause the real bad idle. if you rev the car just slightly (to about 1500rpm) when the idle starts to get rough it clears itself idles fine and the light does not come on.

audifirst

how strong is the flow from the pump ?
I had the same problem and it was bad pump , the flow of air was very light like hairdryer set on low setting,
I have installed new pump and it pumps more air like hairdryer set on high speed, it is much stronger airflow

jschick

I haven't checked the pump for a while, other then it still works. I will check it out, but the really rough idle?

TheSilverBullet

Same here. I was getting a rough idle, similar codes, CEL and poor gas mileage off and on, but increasingly often until I changed out the pump itself. Ever since, it's been perfect with smooth idle, no codes and good gas mileage.

jschick

thanks,
I will start with the pump then.

SloopJohnB@mac.com

Somewhere in the forum there's a tech article on rebuilding the SAI pump. Maybe for another engine, but a search might help save some coin if you want to rebuild the pump///generally there's just a bad bearing innit.

2.7Lturbo

remove pump, code out of ecu, problem solved oh i long for the simple days of my 4cyl jetta lawl

jschick

sorry you lost me on that one? Remove pump, code out of ECU?