Car has just fell on its face, replaced cats as told because of clogging and the were very clogged when removed. Replaced with all OEM Replacement parts and that has not helped. No check engine light during this time. I did throw a catylist light on bank 1 right before I replace manifold exhaust. Check engine seems to be working but not telling me why my car has zero performance and feels like if I drive it, it just may blow up. When in neutral car revs just fine and idles perfect. At stops car idles fine and feels fine and little power for a split second then back to people passing me because I can barely build speed. I have cleaned the MAF sensor and the only thing I can notice visibly is it is about time to replace valve gasket seal, leaking some oil in spark plug valleys.
Change the plugs and leads and re scan as not all fault codes will set a light, also a run on a oscilloscope can shop up any ignition voltage faults, most well equipped work shops can do this test in conjunction with an exhaust gas analyzer check, this is also an excellent diagnostic tool.