Recently my IX has decided that it wants to run lean on cold starts. My O2 will read below 20 for 3-5 minutes then the engine will rev up to 2,000 RPM and the AFR will correct itself. After that initial 3-5 minutes the car seems to operate fine and the AFR stays around 14-15.

Any ideas on what to check?

 

It could take longer than 5 min to heat up the oxygen sensor. So don't worry yourself into an angina.

 

It takes about 10-15 mins for my ix to reach full operating temp in cold starts. But my RPMS are at 2-2.5k when started until gradually lowers to 800 and reaches operating temp.

 

Tonight my evo 8 decided to go lean on start up it was snowing maybe it was to cold idk but when it warmed up it was running fine.

 

To follow up on this. If I let the car warm up it'll idle and drive fine; however, if I shut it off and start it back up in the next couple of minutes it'll barely drive and shows running lean. If I let it sit for another 2-3 minutes at idle then it drives fine. Thoughts?

 

If it's just when the car has been sitting out in the cold for a period of time this is normal, however according to what you said above this is not accurate. How recent is the tune?

 

running lean at idle on cold starts in cold weather isn't a problem, now running lean at cruise/wot is another story. you're fine

 

Had a tune? What sort of mods do you have done?

 

The tune is about a year old now. I should have mentioned this started around the time I decided to mount my pump / e85 switch and managed to blow the fuse to the ecu which prevented the car from starting. Is it possible this could have had an effect on the tune?

 

Possible. Have you had it tuned on e85?

 

Yeah it has e85 and pump tunes. Currently on pump gas.

 

Well thats good, one thing I've learned over the years is that these cars can be really finicky and a good tuner can really take out some of the irritating issues these cars have. So to each his own maybe someone else has some input on this issue?