Hard Start on Warm Engine

[BadMojo]

So, after getting my timing chain and oil light problems resolved, the only major one left is a hard start problem after the car is warmed up.

Example: Car sits overnight and starts up fine. I drive for 15-20 minutes and park the car. I walk in to Taco Bell and order a Grande Combo (all for me, I might add). Once I try to start the car back up, it takes three or four tries before it starts. It kind of struggles and stumbles for a few seconds, almost stalling out before it starts to idle normally.

The car starts up fine when cold and once I get it started, it generally idles fine. It might be a tad rough at idle but it idles at a steady 750 RPM.

Any thoughts, theories, solutions would be appreciated.

Edit: I do sometimes smell a bit of a sulfur smell, and since the cat is original I think it may be on its way out. Car and cat have a little over 100k miles.

[NISTECH]

check your coolanttemp connector and the sensors resistance as well, might be tell ths ecm its colder then it is.

[BadMojo]

Thanks, Nistech. I'll check that. I take it that if the ECU thinks the engine is cold when it's actually warm, it'll dump more fuel in and I'll end up running really rich, hence the hard start?

[NISTECH]

you got it

[BadMojo]

you got it

Thanks, Nistech. I'm gonna check out that sensor next weekend. I bet running so rich at startup is what killed my O2 sensor too...