I admittedly do not know this car, but for some basics..... Check your throttle position sensor and make sure all connectors and wires are as needed. Check values from a service manual. disconnect one spark plug at a time to see if that makes any difference in symptoms. Find your fuel injection system fuse and verify it under load, do not trust visual. I like electronic cleaner spray into the fuse holders. When you say 'checked your grounds'... do not trust a visual, take them apart, sand & clean and put together with dielectric grease over. Run a ground cheater back to battery from throttle body.