I've been having issues with the idle when I first start my truck and for the first 10 minutes or so of driving. After idling in park, rpms would drop lower and lower, then the engine would rev up, rpms went up and then slowly dropped again, etc. When driving the acceleration is "soggy" and sometimes, despite holding the acceleration steady, the rpms would begin dropping like it was going to stall. Only after releasing the gas pedal would the rpms pick back up. It only did this until warmed up, and even then it wasn't everytime.

Replaced the IAC valve and connector tonight. Per Haynes repair manual, I turned the ignition key on for 10 seconds and then off for 10 seconds. First thing I noticed after cranking it was that it idled much higher in park/neutral, around 1500 rpms, which made for a very rough shift into drive. After driving it for 3 or 4 miles and then parking it, it idled around 2000 rpms.

Perhaps the initial problem was not the IAC valve, but it definitely changed something... Any suggestions?

Thanks in advance!