We just went from id1000s and 850cc secondaries to id2000s on e98. The only other change was a 90mm throttle body to help compensate for our lack of plenum volume.

Other than the throttle body occasionally sticking open.. The car oscillates apx 300rpms and has a 3 point afr swing. I monitor fuel pressure and it follows manifold pressure swing that we are also getting.

Ran on AEM series 2. Had 0 issues on the Id1000s... Pulse width at idle is around 1.06-1.07ms and fairly steady. MB/sec is 33.6. I've logged injector phasing from -150 to 150* and nothing seems to help. Pressure tested and vac tested for leaks. Also occasional pop/misfire at idle.. Does not sound cylinder specific.. Plugs were replaced. Compression and leakdown are just fine.

Iac duty to keep 1000rpms is around 15-20%.


Any ideas? Am I missing something?

Jerod