hi all i have a 2001 a6 2.8l, i seafoamed gas tank, oil, and vaccuum yesterday..no problems.
so this morning i change all 6 spark plugs with ngk bkr6egp 7092/ the g-power ones.
i take it out for a test drive drove a lot smoother so i stopped at the car wash and cleaned out the inside, started it up and had 2 check engine lights..

p0507 idle air control system RPM higher than expected
and
p0154 ho2s21 no activity detected

help please!

 

Did you pour the seafoam in the gas? It sounds to me like the seafoam may have damaged your sensors. I can confidently tell you new plugs didn't cause those errors.

 

yea i poured it directly in gas tank...
ive had a CEL for o2 sensor before but it comes and goes..stays on for about a day or 2 then its gone.. happened twice so far..

what is the proper gap for spark plugs? when i pulled out the old plugs they looked pretty bad.. my new plugs were gapped at .032

 

That O2 sensor is bad... the crap coming outta the cylinders prolly pushed it over the edge.

 

Motor Treatments are biggest BS on market. Be happy, your catalytic converter still working
20 years ago i used some motor treatment like SLICK and my engine blow on highway

 

ok so will the o2 sensor cause the high idle? my mech. quoted me 150ish for the o2 sensor, 65 for 1 hour of labor. i plan on driving 14 hrs to california on thurs. and i dont want my car to break down on me lol

 

I'm pretty sure you can get them a lot cheaper than that but i'll let someone else chime in.

In regards to your p0507, you should be able to clear it and if it comes back then you'll have to look at a few things (throttle valve control module, misc. hoses). This one won't turn on the MIL unless it happens more than once, so there's a chance it was just a random event, dunno.

 

Should he have not poured the seafoam into the gas???

 

I used seafoam in my cars numerous times, but never had any problems with it. Anyways, I would start by resetting the throttle body. Just disconnect the battery, reconnect, and turn the ignition to on position without starting the car. Wait about 3 minutes. You should hear the throttle body calibrating. As for the o2 sensor code, check the wiring. If the wiring is good, you can test the sensor if you have vagcom.

BTW, although the plug gap should be irrelevant for your issues, you shouldn't need to gap the plugs. They should be factory set. 0.032 for the plug is the correct gap though...

 

thanks for the replies guys! my spark plugs out of the box were gapped at .037ish?

but i have good news (i think) lol i drove to the park to run, when i returned to my car no CEL's!!
Should i still replace my 02sensor since this is now the 3rd time the o2 sensor light came on?

i really appreciate the replies so far, it was my first time working on my own car lol
but it sure did feel great when i was done! (until the CEL came on haha)