I have a 1986 Mercedes 560SL I bought today, it ran fine when i test drove it but, it but as soon as i bought it and drove out of the guys complex down the street something went wrong, just my luck., it woudlnt accelerate, engine wont rev past idle, and when you give it gas you can just hear it backfire, It runs fine when its cold, or if when i shut off and restart the engine, will drive for a few seconds before it has the same problem, it seems to rev up ok if you dont drive it after starting it, but then after you drive it, it wont even rev up in park, I first thought it was out of gas because it was very low and i had just stepped on the gas.

So on start up when up to tempiture, in neutral, it revs fine sounds fine seems ok. but when i drive it for the first few 100 feet it runs fine plently of power to even spin the tires but at less then a quarter of a mile it starts it wont rev up. even in neutral. just pops and sounds like its starving for fuel when i give it thorottle. From a small test i did, I notice an improvment in idle while this problem accures when i push down the intake flap a little.

Any suggestons?