[automan25]

Yesterday my wife and I went to the pet store. When we went to leave our 02 PT Limited would not start. The engine cranked just fine but it would not catch although you could sense that it was almost there which to me suggests a fuel delivery issue and not ignition. On the way to the pet store it had a pretty rough idle. The car has done this before but the problem seems to away on its own. We let the car cool off for an hour at which point it started, just barely, and we drove home. I would like to fix it for good. Any ideas?

 

[Bob Lincoln]

Always, first and foremost, check fault codes:

http://www.allpar.com/fix/codes/index.html

Often there is a problem with either a crankshaft position sensor or a camshaft position sensor in these situations. Let us know what code(s) you get.

 

[ImperialCrown]

The spark plug tips may also tell a story if they are worn or black with carbon. You can probably at least remove the #1 plug without pulling the intake plenum. A rough idle could be a misfire or rich or lean condition.

 

[jd_1138]

You can buy an OBD scanner for about $40 or so. I bought mine on Amazon for I think $35. It plugs into the large port under the steering wheel. Mine is a little clunky to use, but once you figure out the menu for it, it is simple, and it will tell you a code that you can then look up on Google. The more pricey ones by Snap-On or Mac or whatever probably have nicer menus.

 

[ImperialCrown]

There may not be a active or stored fault code here as the OP didn't mention a 'ck eng' light being on. If the light is on, a code is stored. Most auto parts stores will check them for free (don't buy anything just yet).
It may take awhile to set some fault codes with a rich, lean or misfire condition, but they will eventually set under these conditions. It will first appear on a scan tool as a pending code or 1 trip failure before it ripens into a true fault code.
I agree that there isn't enough information here yet and some preliminary diagnosis/observations may give us more to go on.