when l star my engine start shaking is this normal
have a too much fuel pass trough intake , my mechanic say is the ecu. but we change allreadybut still burn too much fuel whats wrong ?

LOL, how you expect ppl to answer that?
Theres only 3 answer will appear,
1. YES
2. NO
3. l Dont know, take it to the shop.
Now, l alrdy gave 3, pick the one you feel most comfortable to hear ;)

Is it cold where you live? If so that could be the reason for it. Does it run fine? Does it sound like it wants to stall while sitting in park? If so this could be an O2 sensor problem. l had that issue with my subaru, but l had the ''check engine'' light on.

A little rumble and tumble is fine, it is a burly little boxer 4 after all. as long as the problem is only on startup. If you are experiencing this while idling, then l would have the O2 sensor checked and it could possibly be the ecu but if you've had it replaced, that would be unlikely.

if you are using BP ultimate fuel this could be your problem, a race mechanic told me it leaves a coating on the plugs when it cools. My 95 WRX did the same thing when it would start then it would smooth out. l use the caltex vortex now. and no dramas.

Good luck l hope this helps.