Josh S4

It's been doing this for a while and 3 days ago i installed my mtm chip and did a throttle body adaption and then my car was running smooth as can be. but now a few days later its shaky again. no dtc's were thrown. any suggestions? thanks!

AxelS4

What fuel are you running? I had the same with Chevron (different chip, although), went away with Shell, 76 is sort of in between. Also, check your spark plugs. If you constantly run short trips, go for hotter plugs; if you run long trips ONLY (or track the car), then go for colder plugs. The OEM ND plugs are ok for mixed use, but not exclusively short trips.

Josh S4

any spary plug recommendations?

A4edge

been concerned and posted on this before, no codes, dealer never addressed...mentioned it every service...?

macdarren

My stock and MTM do this too.

I Know the 2.7T A6 have it as well...

I notice mine after runing hard then coming to a stop.
I have been told that the car leans out a bit when hot then having the thottle plate closed puts it real near a lean miss condition (told this by a service rep and an audi mechanic) The deal is since it is right on the edge of a lean miss if the fuel is not perfect (and here in CA is seldom is) then you get a occasional miss which causes the shake. So far the only problem I have seen is that friends think my so cool S4 is not so cool since it runs rough...of course the WOT drag to the next light generally changes their mind.

Darren

AxelS4

First: It won't destroy the engine - so no worries. It is just a nuisance, and dealers mostly "fix" it by adjusting idle speed up. Do not let them do it. Second, there are Nippon Denso and Bosch plugs out that would achieve what you want. A dealer should be able to give you part numbers for plugs that work if you explicitly tell them you do a lot of short trips and the engine never really gets hot enough. That mostly triggers something within these rocket scientists... But I can look up some Bosch part numbers if so desired. Other solution: Get more exercise - for you and for the car...

AxelS4

Yes, that is the explanation if you do not do short trips all the time and basically have carbon deposits all over...

Waseem // TMK

it sorta alludes to being able to adjust the idle
yourself by doing an idle adaptation. haven't
tried it yet, but i might since i have had the
same problem as you recently.

in addition, take a look at the denso iridium
site, they have info on what colder plugs vs
hotter plugs are for, and when to use each.
colder should allow the car to run richer, which
is good if you're chipped... but they might
foul out quicker. however, like axelS4 said, for
normal street driving, without a lot of high speed/high boost driving,
you probably want to go with hotter plugs.
denso's stock heat range plug is ik20.
the colder plug is ik22,
and the lower the number, the hotter the plug,
the higher the number, the colder the plug.
ask the guys at denso, they were a great help.

AxelS4

yes and yes, and the idle adaptation works. I had to reduce the value again because the deler made mine idle way too high. Easy and fast with the VAG-COM.