This all came on quite quickly. It was fine in the morning, then after lunch it idled roughly at a few stop lights. Then in the evening it was misfiring badly and the a/f went off the charts (17's). When I start the car, it runs ok, with so-so a/f for about 3 or 4 seconds, starting from slightly rich, then fine, then leans out.

What do you think would have made this problem happen so quickly?

 

Maybe fuel pump? Possbily bad gas? What ems are you running? Are you still gettng misfire after put new plugs?

 

It is just the stock comptech setup for now. I am researching ecu upgrade options, but step one is to get it running again.

I swapped fuel pumps, but it didn't help. With fuel pressure at a steady 55psi, I figured that the pump was fine anyway. It could be bad gas, though I have been going to the station I always use, so I wouldn't think that would be the case.

The iridiums are special order, so I won't be able to try them out tonight. I guess I will look at the MAP, IACV, and replace the gas.

 

It magically fixed itself when I got home from work.

I decided to clean my iacv anyway. I forgot to plug it back in after the install and it replicated my earlier issues. I plugged it back in and everything was fine.

 

Also, that design is really bad! If the gasket goes bad, coolant will leak into the manifold. Does anyone ever remove all of the coolant lines going into the throttle body and intake manifold?