2000 Monte Carlo SS with the 3.8 will start and idle and stay running when I shift into reverse or drive,until I accelerate.at which point it dies,every time. When in park or neutral and I depress the pedal it sounds like it is sucking air then dies . Always restarts but continues to do the same. I have unplugged MAF,IAC, IAT.all at different times. They all change the idle and the way it runs in there own way. The only maintenance I have done recently is changing the fuel filter. I did that only because it hadn't been done since I bought the car three years ago. Any hints,tips or good advice will help. If anyone needs more info I will be happy to provide it

 

I would start with cleaning the IAC, but it usually needs to be replaced if mileage is high.
I would also clean the MAF with MAF cleaner, then the throttle body. Scan for codes.

 

A couple of things to check
1. is Vacuum line could be off or broken. Check the drivers side engine area going to the firewall for this line, goes towards the but not into the master cylinder for brakes.
2. Could be the Catalectic Converter is bad and they will fill with its own packing.

 

Will check on these things in morning and grab a can afford cleaner and let everyone know how it works out..Thank you for your quick response!

 

I was going to agree with a plugged converter/ exhaust. Pretty hard to clean out a converter on a car that won't run, but there is a product called "CataClean" by Mr. Gasket that actually works. You have to be able to take it for a drive though