1995 Sonoma - Surging at Idle

New to this forum and looking for advice please. 1995 Sonoma 2.2 Liter L-4 engine surges at idle but OK under power. Replaced plugs & wires; no joy. In-law suggested new Idle Air Control Valve (looks like a solenoid, mounts to intake plenum). Well, $70 later and no joy. So far have replaced all plugs and wire with good quality stuff (but had great difficulty with plug boots and still not confident that they're down tight) and the IAC valve. No alarms; no codes. Vehicle does not stall in idle but is pretty rough. Ideas? Willing to try and buy anything short of replace motor. Truck has 165K miles and we still use it for utility.

Welcome to the forums. Does the truck idle good and smoothly when its in gear? How about whenit cold, or hot, any difference? Make sure you have no vaccuum leaks, or didn't pull something off like the brake booster hose and forgot to put it back.