your right,it is occasionally hard to start,but only after its been started and let to sit.ive been noticing its starting ok,it just needs to warm up a bit then its fine,i have not checked the other sensors,i was about to replace the temp sensor.there is 2 or 3 of them,im not sure wich temp sensor controls the mix.what is a lambda sensor?,im not familiar with that one.i still need to replace the o2 sensor also.