Originally Posted by Giovonage
So my car has a new problem. Got off work yesterday and went to start my car and it really struggled, it took 3 or 4 times to get it to turn over and idle. Once it started it had no problems running or idling at all. I got home and pulled the code and it came up p0171, system too lean. Any ideas? I was thinking maybe a vacuum leak but its strange that the engine only seems to struggle when starting up.
I've replaced the 02 sensor, the spark plugs, the coil packs, cleaned the MAF sensor, all within a couple months so i dont think its any of those...
System too lean can also be the MAP sensor that isn't working as it should. In some cases they get sticky and hesitant to move.
Do a data log if you can and make sure you log rpm, maf, map and throttle opening.
If the engine hesitates when flooring the throttle at lower rpms and the MAP sensor doesn't follow up in pressure change then you have caught the culprit.