A liitle help needed here!
Been suffering from an incredibly Lumpy idle for a while now occasional stalling too!
Replaced the iac valve and throttle position sensor but not a great improvement!
Just put an OBD reader on and got the following:

Calc. Engine load Min 2.74% Max 3.92%
coolant temp Min 172.4f Max 172.4f
short term trim 1 Min 66.40 Max 66.40
Long term trim 1 Min 23.43 Max 23.43
short term trim 2 Min 84.37 Max 56.25
Long term trim 2 Min 23.43 Max 23.43
Fuel pressure Min 765kpag Max 0 (?)
man air pressure Min 9.715 psi Max 12.615 psi
RPM Min 913 Max 1170
ign advance Min 7.5 deg Max 18.5 deg
intake air temp Min 80.6f Max 80.6f
Air flow Min 3.28 g/sec Max 5.57 g/sec
Throttle pos min 0 Max 0.39%
02 sensor 1 min 0v Max 0.02v
02 sensor 1-2 Min 0v Max 0.445v
02 sensor 1-3 Min 0v Max 0v
1-4 min 0v Max 0v
1-5 Min 0v Max 0.025v
1-6 Min 0v Max 0v
1-7 Min 0v Max 0v
1-8 Min 0v Max 0v

Also throws up occasional p0121 and P0122 codes as well!
Only thing I can think of is that I lost the screw in gas cap and it has a temporary push fit one on there....... surely not??
I'm thinking maybe Intake manifold gasket (s)??

Thanks in advance!!