Hi i have a Suzuki jimny model 99. I just chanced the head pack Bud when i am driving in gear the check engine light pops up and i can feel the car loose a little power for 1 sec. this only happens when i am pushing the gas pedal and have it in gear. Bud when going down hill with it in gear and in 2000 - 3000 rpm not pushing the gas pedal it runs ok, holds and check engine light does not come on. only when i am pushing the pedal What could be the problem and how can i fix this ???