My 92 f150 bucks and jerks bad when trying to hold the throttle steady. So much though that it wont take an emissions test because it cant stay at a steady speed. When I checked the code I get system to lean code. I'm thinking a fuel filter. I just did a full tune up on it and it is still doing it. What do ya'll think a fuel filter or something else. Thanks for any help in advance.

 

TPS, vacuum leak