Does anyone know if a 2003 Suburban 1500 with a 5.3L Flex fuel engine has an IAC valve? I am trying to troubleshoot an idle issue and was hoping it was something easy like cleaning the IAC valve. Here is the issue: My normal op temp idle drops below 500 RPM and once and a while stalls when stopping or going from reverse to drive when backing out of the driveway for example. I tried a reset of the PCM by disconnecting the battery and re-programming as directed in the Chilton manual - but this did not seem to adjust the idle to the targeted 650 RPM. My next course of action will be to get out the carb cleaner and spray down the mass airflow sensor and see if that helps. I have approx 120k miles. Plugs and PCV are new at 100K and air filter (K&N) is clean. One other observation that may or may not be associated with this issue. I have also noticed some knocking under full throttle acceleration and once and a while the check engine light illuminates during a full throttle jaunt when getting on the expressway. I have not had a chance to check the code with a scanner and the light normally goes off when the engine has been turned off for an hour or so. I have been told that this may indicate a clogged converter. I am hoping it is something less costly which is why I was looking for the IAC or associated components. Any ideas?? I am baffled... Thanks in advance!