hey, I have a 1995 chevy 1500 with a 4.3l tbi engine, it developed a terrible misfire, I just replaced the whole exhaust system the catalaytic converter was completely clogged so I figured that was the source of the misfire but it wasn't the truck runs a lot better but the miss is still there, it is only while the truck is idling in park or drive and when it hits overdrive, it runs excellent when it isn't in drive or in overdrive, when you go to take off it hesitates for a second then takes off and runs fine, it doesn't appear to have any vacumm leaks, I just replaced the fuel filter which was quite dirty, if some one can help me diagnose this it would really help, thanks!