A friend of mind has a 91 grand prix with the 3.1L engine and it runs fairly fine, but studders occationally, but when slowing down to a stop like at a stoplight, the car with studder and die. Now if the car is in Park it will studder, but doesn't always die. SO i'm thinking it's something in the ignition system or maybe the intake (upper and lower and MAF need to be cleaned. Also when driving my friend says there is a 'horrible grinding noise, which is why i stopped driving it. " I do't know what it is, but any advise would be appreciated.
