I drove my 04 wrx to South Lake Tahoe for the first time since I bought my car a few weeks ago. I'm in San Francisco at sea level, the area of Tahoe I was at was about 5000+ feet above sea level. As soon as I get to Tahoe, I notice a serious lack of power when I'm accelerating from a stop. I understand that due to the thinner air at higher altitudes, performance will decrease to a certain extent... BUT my 4 year old nephew will out run me across an intersection (not that I tried... but he could have) ! It can take about 4 seconds just to make it halfway through the intersection. Once I build up speed, It'll be ok, but there is a SERIOUS lack of acceleration from a stop.
First, I thought maybe my wastegate might be stuck open or something from running 3000rpm for 2 hours, but when I drove home and got back down to Placerville, my car accelerated near normal speeds... and back in the nice, cold, dense foggy air of San Francisco, boy does it accelerate.
I'm no expert in Subarus, or in turbos for that matter, but I thought the ecu would use either the MAP sensor, or a baro sensor if it's equipt with one to read atmospheric pressure and compensate.
I'm hoping someone can shed some light here on what might be going on. I haven't found anyone else with the same problem online... and I couldn't find any TSBs in this matter. For reference, I'm running stock everything except for a SPT intake and exhaust.
Any info that can help out here is much appreciated!