check for codes being thrown. coolant lines leaking and there are a couple sensors to check too. ect, the one next to it on side of head and there is one on back of block near the right corner too. sorry i dont know the names of them all but know about them cause i replaced them all lol. ect could be bad too, i put in a new one and it threw a code 6 (ect code) and then i put the old one back in and no codes and everything is good. also maybe try the ground that is bolted next to the thermostat. i just did my head gasket too and have one issue besides the code 6 but i won't hijack ur thread. 1100 rpms is ok for warm up but then idle should go down to 750-800 rpms for idle according to haynes manual. i cleaned the iac, fitv, throttle body and my intake manifold and my car has never ever idle like it does now. 1500 rpms start up;2-3 mins later down to 1000rpms and then 2-3mins after that 750rpms and holds there and car is at normal operating temp....even after running it hard or just chillin at stop light 750 it is lol. try adjusting idle through the fitv or throttle body or both. hope this helped and good luck man.
