Acceleration issues
why not let the mech do his/her job.?
you have not stated yet,
engine power issues. (nor engine displacement)
or transmission problems, slip? or shifts wrong.?
it's one or the other, and is the JOB 1 to find out which it is
and it's a fact any mech can answer that in a trip around the block
did he noT?
all A/T trans do stay in 1st and do accelerate, but then shift 2nd
read the FSM it shows the exact shift points in a graph. RTM.
if you dont understand all that, then let him do his job.
and btw, A/T trans are very complex. and have 100s of parts that can fail and leave you stranded. just one cracked 0-ring and the world is dead. NO GO.
a loose spark plug is bad service, dont go back there.
Find a real ASE Mechanic, (on badge on sleeve it is)
he never used a torque wrench, and with alum. heads its critical to get it RIGHT.
the trans failures, can be bad TCM function any TCM input , any TCM output (TCM is a function inside your PCM) any bad solenoid.
bad sensor , or bad trans mission.
finding it takes hard work and owning any A/T means big labor costs and or $3000 new tranny. that is what you get with an A/T
toss a coin.
a loose wire, or a $3000 bill and $1000 labor
fate. (10 year old car how many miles, now> 300k?
TCM = transmission control module (or function)
PCM , power train control module, can have TCM in side it)
bad engine
bad trans
is the CEL glowing? driving?> scan it.
if not in USA scan it anyway, as some countries have CELs that lie.