1992 Chevy Lumina euro 3.1 stall, surge and hesitation issues

1992 chevy lumina euro 3.1 V6 - 174000 miles stalls, surges, and hesitates intermitently on take off sometimes when engine is cold. It idles funny, too. Also sometimes stalls after being driven for about 5 - 10 miles when it has warmed up. No service engine lgt is on right now. It sometimes stalls running down the highway at about 45mph. The problem started when the service engine lgt came on a few weeks ago. The code was 22 for the TPS sensor, so it was replaced, it had previously been replaces about 9 months ago. The service engine lgt went out, but the stalling an hesitation problems continued. Change the crankshaft position sensor. Did not solve the problem. Cleaned the IAC valve, it was replaced about a year ago, this did not help. It hesitates on take off sometimes. Could there be a problem with the Egr valve or TCC solenoid. I was going to look at the fuel pump and fuel pressure regulator next.