ok so i am new here and new to the isuzu world. i got a pretty good deal on a 96 trooper in amazing shape the person who sold it told me that it has a couple of quirks so here goes and what i have done so far.

it is throwing a p0304 (cylinder 4 misfire) and every now and then after i clear the codes it gives me a p0300 (random misfire) im more concerned with the first p0304 i changed the coil packs around (switched 3 and 4) and same problem i have replaced all spark plugs with brand new NGK's and replaced 1 coil pack (put into cylinder 4) still nothing.

it has a high pitched noise (possibly vacuum leak???) coming off of the drivers side of the motor (bank 2 i believe) ive been checking this for awhile today with starter fluid...

it is missing the catalytic converter on the driver side also (getting new one tomorrow).

it is also burning some oil about 1/2 quart every 250-300 miles...

what i am most concerned about at this point is how to get this misfire dealt with does anybody have any suggestions??? im sure that i have forgotten something that i've done to it... i thank all in advance on any help with this

 

Try switching around some plug wires, pull the wire off #4 and check for any burn marks anywhere around where the wire enters the head, could be randomly arcing through the insulation.

 

94, same thing. that plug fouled first when time for a change. as for the whistling? same here. I'm going to replace every hose I can find. Keep me posted. Good luck