2005 Buick Rendezvous with the 3400 engine I have problems with is occasionally overheating but it is not very often I find it hard to start after driving for awhile and when you park at idle it knock?

Answer 1

Sounds like a classic fuel injector problem. One or more injectors may be leaking ever so slightly after the ignition is turned off. This leads to a cylinder filling up with gas and engine flood condition. Problem will surface most prominently in hot weather and when you turn off the car then back on in less than 10 min. If you let it sit long enough the extra fuel evaporates and you don't have the flooding problem. Else you can keep on cranking the engine to expel the extra fuel and get the engine normalized (probably what you're doing now if it does eventually start). Off chance that using a good fuel system cleaner will fix the problem; worth a try.