87WSP5.0

When driving the cars power will cut out (acts like it is missing or stumbling) then comes back in hard and poping sounds will come from the exhaust. Idle is rough, the engine shakes alot at idleand when you lightly tap the gas in neutral it revs to 3k and slowly comes back down to idle. Timing is 10 degrees (firing order has been checked), plugs, cap, rotor and wires are new. Fuel pressure is 43# and droping it or raising it did not make a difference and there are no vacuum leaks.Mods are full exhaust, 70mm TB, C&L (19#)76 MAF & elbow, and Typohoon intake manifold. Any ideas of what to check?


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nitrous_bob

try plug gap

if they are platinums or something else stupid....ditch them

gap them down to about .035" and see what happens.

then if that does nothing......you need to check fp off the rail and what it's doing under load

** but ** i know you said you checked it....... first thing comes to mind is firing order, burned wire, or a boot not on all the way

mjr46

you say you have no vaccum leaks?? there are hard to get to places that spraying with carb cleaner won't reach...the best methood I use is a smoke machine..but i KNOW MOST PEOPLE DON'T HAVE ACCESS to such..so my first inclination would be to find a shop that has one and have it tested for such...but first things first..you can perform a koer /cylinder balance test and maybe locate a prob that way....any codes??? maybe the egr valve is hanging partially open??...if it's a MAF equipped car..maybe a bad maf or dirty....if it's an ignition prob maybe it has a bad or cracked coil..lightly mist the coil with a spray bottle and look for arcing = bad coil if it does

XXC

Hey look, we have the same problem!

To bad I don't know what mine is.

Do you got a MSD box?