930 Turbo Hesitation/ Bucking
I recently started having a hesitation/bucking problem on full acceleration! The timing is perfect, the plugs are great, the distributor is perfect, the plug wires are new, the ignition coil is great, the fuel injectors were poptested and all passed, the WUR is new, fuel distributor is rebuilt! Upon starting the car it feels like the cold start valve helps to relieve the hesitation. I can rev up the car and there is no hesitation at all until the thermal time switch shuts off the cold start valve then that is where the hesitation is noticeable! The idle is rock solid when the engine is cold or hot! The rear fuel pump is a brand new unit! But the one in front is a rebuild that was put in 2.5 years ago! The rear fuel pump works perfect. Oddly the front fuel pump upon starting the car does not seem to activate the red relay in the fuse panel as it used to! I seem to only feel the hesitation/ bucking when the car is being driven around 2000rpm to 3000rpm and then it clears up! I believe that if this was an air leak issue then I'd see a hunting idle! And if the CO% was out of place then the idle would be osculating! But in my case the idle is rock solid!
Also if one of the cylinders was leaking air, could the idle still be rock solid, or would it affect the idle? Would it only affect the drivability on load?