1997 Chevrolet Cavalier

Engine Performance problem
1997 Chevy Cavalier 4 cyl Front Wheel Drive Manual 146000 miles

my 97 z24 has been acting up for the last week. It stalls when shifting and does it whenever. Today it stalled a lot and also didn't idle good and I got the engine code PO674, which is glow plug circuit: cylinder 4.

my question: I have changed the plugs, boots and ignition coils, inspected the cover, is there something else I could replace to fix this problem? Asap, my daily driver! Thank you
November 9, 2010.

Is this a typo?

PO304 maybe?

No it came up as P0674, which I found out is a cylinder 4 misfire. A mechanic said change the plastic casing that holds the ignition coils, because perhaps a spark would be firing out the side of it. What do you think?

Nov 10, 2010.
I haven't heard of that code and a cyl 4 misfire is a po304. That I do know.

I would check compression on that cylinder. IF good I would swap the #3 and #4 injectors and see if the miss moves.

A housing is certainly possible, but more often gives a multiple misfire code ( po300)