1) Is MIL/CHK engine light on?
2) How many miles are on your car?
3) If Chk Eng light On,check DTC codes at AutoZone or Pepboys.
4) If NO,we are going to look at the throttle body for Cleaning + maint.
Lost HP with no codes is a symptom of a dirty throttle body,IACT & MAF sensor, it also can
cause random misfires on random cylinders while trying todo a WOT condition.
Spark plug Gap = .035-.039 NGK iridium
Physical cylinder, not firing order.
V6
TRAN
3 6
2 5
1 4
FAN
V8
TRAN
4 8
3 7
2 6
1 5
FAN
A Throttle plate will get stickey + Not get the response,the PCM needs a good signal.
You need alot of Air to produce 400HP.
Also clean PCV vacuum port on Left frnt side valve cover going to the throttle body.
This port provides breather Air when throttle plate is closed.