2007 3.8L AWD Endeavor w/34,000 miles.

About two years ago I installed a K&N air filter. Engine ran fine until a few months ago when it developed an inconsistent miss at idle w/a cold start. The miss would last about 2-5 mins. while driving, but only at idle such as when coming to a stop at an intersection; no miss while unnder way.

I cleaned the crud from the throttlebody w/o any change. I also cleaned and recharged the K&N filter w/no change.

Took it to the dealer under warranty and they said it went away w/the MAS disconnected. They installed a new one and it stopped missing for 10 days and then returned, but less frequently; again w/o a check engine light. They tried an OEM air filter w/no change and told me to drive it until the "check engine light" turns on so they can extract a code.

I'm thinking of cleaning the MAS and reinstalling the OEM filter as a test. Your opinions are much appreciated; thank you in advance.

 

Don't know how much different the 07' 3.8 is from the 04' 3.8 but I have had a K&N filter installed for four years now and have only experienced what you posted once and it went away and never came back. I am assuming the outside air temperature was summer temps wherever you are at. I owned a 97 Eclipse when I lived in RI and man did it hate cold weather. It would miss and idle rough until it warmed up and only when it was really cold.

My 2004 Endeavour has only done what you described once to me and it never came back. It wouldn't hurt to eliminate the K&N by putting an OEM filter in but I bet the problem would still be there. The fact that it does it at idle only should eliminate the filter all together. If it was an air problem wouldn't it get worse the more air the engine was sucking? I would poor some injector cleaner in your next gas tank and I bet that fixes your problem. Keep us posted.

 

King Jaga:

Thanks for the response. I was thinking along the same line. I put the OEM filter back to see if it clears up the condition. I will use a can of SeaFoam in the next fillup and hope it stops. Again, many thanks for your thoghts.

 

We are having a similar issue with our 2007 Endeavor.

Rough idle/miss on a cold start, once the engine warms up it seems fine. Occasionally, the engine will run so rough the TCS light comes on. Been to Brien Mitsubishi twice, first time they just cleared a code, the second time they said there was a lot of carbon build up and charged us close to 200 bucks to clean it. Seemed to run fine for a week or two and the problem came right back. Now the TCS light has come on 3 times in the last week

 

My check engine light has not yet come on. Did the dealer clean the throttle body? It can gum up and cause a rough idle. You can decarbon the engine yourself w/SeaFoam thru a vacuum port. Put a pint of it in the gas tank next fillup and it will clean the injectors and the valves. I use Pennzoil synthetic oil designed to clean the inside of the engine; it works quite well removing built up gum and varnish as shown by the dirty oil.

 

btp2k2 run your Endeavour down to an Autozone or some place where they check the codes for free. Then do a search online for the Code to find out what it is. Sounds more like you have an ignition problem, bad plug or wire or something. How many miles are on your Mitsubishi?

 

All,
i have a 1995 montero sr,, i had the engine rebuilt 2 yrs ago and it ran great, until recently. Now it has a problem starting , takes 3-4 tries used to start on first try. also while its cold, it will not idle, ii have to keep feathering the accelerator or keep the rpm's up. it does this for approx. 20 min. then it runs perfect, idles just fine etc. this occurs from every cold start. i do not know exactly what changes when the engine goes from open loop fueling to closed loop fueling. i have replaced the fuel filer, and the air flow/temp sensor, neither one made a difference. i use a pc app called evoscan ver 2.9. i have reviewed the info but nothing stands out, yes a service class would be great, but oh well. attached is the evo ecu data i pulled, any help would be appreciated