Engine Performance problem
1995 Buick Riviera V8 Front Wheel Drive Automatic 120000 miles
----------------------------------------------------------------
The Riviera is supercharged. After sitting for a good while (usually overnight), it stutters when I try to start it. (Just like my lawn tractor does when it's cold and I don't have the choke properly adjusted). If I give it gas, it dies. After it dies and I try to start it, it ssounds just like older cars do when they are flooded. If I wait 10 minutes and try to start it, sometimes it starts and sometimes it stutters again. After doing this two or three it eventually starts. Once it gets going, generally it works fine...but not all the time.

I have replaced: the fuel pump and module, the crank sensor, the coolant temperature sensore, the ignition module, the fuel filter...and I have checked the IAC to make sure it's ok

You may have a vacuum leak, get a can of spray gumout, spray the vac lines and maniflod area, when the idle changes, youve found the leak! You want the engine running and spray on the outside but do direct the stream onto the hoses, if it is a vacuum leak, the engine idle will change speed, then you have detected a leak, repair the vacuum leak and see how it runs! If that doesnt do it, you may need a new idle air control valve, it's bolted to the throttlebody. I know you saif you checked it, but they are tricky, one backfire, even if you didn't feel it can destroy em! Is the SES on?

no the ses light does not come on

Meant to tell you thanks for help

Let us know if this helped...