vern1

I had the 60k service done in the spring. In the past couple of months, most mornings the cars starts rough ie hesitates for a bit then catches - has stalled a couple of times. Always fires right up the second time if it has stalled.

After that there are no problems. It idles fine even when cold and pulls away with no hesitation and pulls hard from there. It only happens in the morning. If I park the car at work (or anywhere else) and then start it up afterwards, there is no such issue.

I did check a few previous posts but didnt find anything quite like it. ie most other issues involved a rough start and then a rough idle (which is not an issue for me). There were some suggestions it could be the ISV. Any thoughts?

Thanks

Steve Weiner-Rennsport Systems

I'd be suspect of the fuel pump check valve.

This is what holds fuel pressure in the rails when the engine is off and when they leak, fuel is allowed to run back to the tank. This affects starting & running until the pump builds up pressure in moment.

vern1

Thanks Steve, is this easy to get to (not much is really!!). However I am curious as the car sits just as long at work as it does overnight most days and i never seem to have this problem after work - just in the mornings.

Steve Weiner-Rennsport Systems

As you can imagine, its not easy to troubleshoot anything from afar so all I can do is offer "blind" suggestions based on some experience.

These kinds of problems can be intermittent and thats what makes such issues so challenging. Your problem may be temperature related so I would try two things:

1) Install a fuel pressure gauge into the rail and see if the pressure bleeds off overnight.

2) I would also check the head temp sensor and its connectors as that also affects cold starting. The resistance values & temperatures are all in the factory shop manuals.

Performing these tests prevents you from spending unnecessary monies on parts that may not be defective and these procedures is what I'd do if you were here.

Short of doing this, I'd begin by replacing the Fuel Check Valve as its pretty inexpensive.

vern1

Thanks Steve for the expert advice. Most of that is well beyond my experience but I will see if I can dig into some of it.