99 boxster codes after 2k rpm

[bobbyb]

Hello ,
Working with a Friend on his boxster. It runs great until 2000 rpm and the codes p0300 p0301 p0302 p0303 are present . Check and clear codes and it is fine again until 2000 rpm. Any help would be appreciated.

[JFP in PA]

You have all the cylinders on one bank of the engine suffering missfires.

[bobbyb]

Correct
But only after 2000 rpm
It will idle all day with out codes. Once 2000 rpm or above basically the passenger side of the engine shuts down

[JFP in PA]

So what diagnostics have you done on that bank? How are the coils, the plugs, and coil wiring connectors? Have you scanned the engine for fuel trims? What do the cam deviation values look like at idle and at 2K?

[bobbyb]

Coils,plugs and sparkplug tubes are new or parts from local dealer. Have checked connectors at coils several times. Fuel trims look normal. Do not have a way to check cam position sensor. I lean toward that being the problem. It loses the pass side spark every time at 2k. Fuel pressure and filter are OK too. It seems mechanical /trans rpm dependent to me

[bobbyb]

Coils,plugs and sparkplug tubes are new or parts from local dealer. Have checked connectors at coils several times. Fuel trims look normal. Do not have a way to check cam position sensor. I lean toward that being the problem. It loses the pass side spark every time at 2k. Fuel pressure and filter are OK too. It seems mechanical /trans rpm dependent to me

[JFP in PA]

You need to get the car on a PIWIS or Durametric system and look at all the values, including the cam deviation values.............