H6 rough idle and check engine lights on cold start

[cosa8904]

Hello all, I have a 2006 B9 Tribeca with about 160k miles.  Just purchased the vehicle about a year ago, but shortly after purchase it began rough idling when cold started, and the cruise control, traction control, and check engine light have been coming on intermittently.  Occassionally the check engine light flashes, then reverts back to staying on.  Once the car has run about a minute or so it idles smoothly, and sometimes the lights go off.  So far I have had all the plugs replaced at the dealership, but that didn't help.  The mechanic I took it to last seemed to think the valves were out of adjustment, but that didn't sound right to me, and the expensive head job he suggested to fix it isn't feasable.  Anybody have a similar experience?  Any recommendations?  Thanks.

[cosa8904]

nobody?

[Fairtax4me]

If the check engine light has been on and flashing, there will be codes stored in the ECU. Take the car to an auto parts store and ask to have the codes scanned. That will help narrow down possible causes.

 

Once the engine is warm does it continue to run rough? Does the CEL still flash after the engine is warm? Or does it only do that when the engine is cold?

 

Most often a cold engine misfire will be a fuel problem. Dirty injectors or low fuel pressure, or something like a bad temp sensor making the fuel mixture too lean.

If the misfire is continuing once the engine is warm, that is more likely to be a spark related issue.

 

Get the codes scanned and post the "P0xxx" code numbers here and we can get a better idea of what's going on.

[1 Lucky Texan]

nvrmd

Edited February 2, 2015 by 1 Lucky Texan

[cosa8904]

will do, it only runs rough when cold, and only for about 30-40 seconds.  It spews grey smoke during that time and smells like gas (like it's running rich)  After the initial startup time it runs smooth, but the lights stay on most of the time, and only go off when I try to take it in to get it diagnosed, lol.  Check engine only blinks when it's running VERY rough a few seconds after startup and not every time.  I guess my biggest concern is that it's something other than fuel or spark (which I figured it would be) until my mechanic came back with the stuff about the valves, etc....I just ca't imagine messed up valves would suddenly run smoothly after 30-40 seconds of run time....it didn't make sense to me so I wanted to run it by you all to see if anyone has had a similar experience and knew a fix.  I will post codes as soon as I get them....the last code it threw was for "misfire" I know that's too vague without the actual code number, but it's been awhile and that was before the plugs were swapped.  I will get the codes and update soon.  Thanks for the replies. 

[idosubaru]

get the codes.

 

flashing means multiple cylinder misfire so some of the check engine lights are probably cylinder misfires, which are often caused by:

 

1. oil in the spark plug wells - replace valve cover gaskets and spark plug tube seals

2.  plugs are old

3.  coil packs failing

[cosa8904]

thanks for all the replies....got tired of trying to deal with the car and traded it in today for a brand new Crosstrek!  Hopefully I'll enjoy my new Subi more than I did the last one.