I've got a very bad miss at high rpms now that i put my new exhaust on. One of the pipes is hitting the under side of the car pretty bad on hard accelleration. Could this be causing false knock? And if so can false knock feel like a very bad miss?

 

Missing at high RPM - sounds like an ignition issue

false knock causes retard and a loss of power buut not a miss.

I used to get it a lot at acceleration from traffic lights - the car would stumble and have little power - Got a scanmaster and discover 10 degrees of retard was occuring

you may have a tired coil or ignition system (if your running one) - arcing/ poorly gapped plug or opti issues

 

its hard to tell what is happening, i have'nt had a chance to put it on a scanner yet. But it only happens when the exhaust hits, so it is hard to tell what is going on. But i can tell a dramatic decrease in power. Everything on the car is very new. Motor only has about 1500 miles. Same milage on everthing including opti, wires, coil. Plugs dont even have about 100 miles on them. The problem got real noticible whent the exhaut was put on.

 

Yes it can feel like a miss. They do feel a little different but are very close. If you think you have false knock oder a LT4 knock module.....you won't be sorry........makes the car more consitant and i knocked off .3 in the 1/4 due to false knock issues (headers)

 

I have a 93, they do not have knock modules like the they have in the 94 and ups.

 

I doubt you will feel anything that seems like a miss from knock retard. It retards the timing, not cuts out any spark. About the only thing you would notice is that the power was down.