I was riding down the interstate at 1130 PM, low 70 deg, about 70 - 80 mph in 5 th gear and i let off the gas completely to slow down a tad and BAM and i'll i saw in rear view mirror was this light,acutally i saw it out of all mirror and window. So i tried to do it again,and couldn't , but aoccasional little pops. So i get home put the car in nuetral and idle is jumpy 200 - 600 when my normal is 1000 rpms. Car is sounding like it's sick. Shaking and puffs of black smoke out of the exhaust. I waited 5 min started it back up. Everything is fine Vac 18 on boost guage and 900- 1000 rpm on the idle. So the next day i drive it, i'm getting studders through the rpm band 1-3 to about 4,500 rpms in each gear. I go 2 blocks stop at light,and the idle is doing the jump between 600- almost 0. So i pull over car isn't stalling but sounding like it's gonna,with black smoke coming out again. On the way home it backfires about 5 times,the loudest dam backfires i everheard. I'm not gonna be surprise if my muffler is split wide open. Anyways i checked the Map sensor hose. It's attached to the sensor and to the engine . What else could cause this problem. This doesn't mean my engine is toast, just a rich issue i hope.

Mods:

Blitz intake

M2 downpipe

midpipe

Greddy PE exhaust

HKS Fcon fuel computer

are your coils ok?

Sounds like an air leak to me. Check all the pipes and inlet manifolds for leaks.



Get a long length of hose, put one end you your ear, and move the other end around the engine bay with the engine running and listen for gushing air.



Dan