95 pontiac bonnie, car started missin as i was driving, came hame inspected plugs, wires, coils all one at a time. no cracks leaks or anything, no fouled plugs eitha. when and had a DTC scan and it came back with a code for the knock sensor, and a misfire. changed knock sensor and had it rescanned, same problem. rechecked ignition components again and no problems found. gonna do a compression test 1st thing in the mournin. my question is if it comes down to the cylinder head, should i replace both if i get them fron a bone yard ?

when you checked your coils did you pull wires off as it was running or just do a ohms test

Cylinder heads are unlikely.

Is this a naturally aspriated car ?

yea i checked while it running, replacd coils plugs and wires, all are firing at coils, even used a spark plug tester. checked injectors with car running all fine, compression test cam back great.

How is the coolant level?

If it'* low at all, please read up on the upper intake manifold failure or UIM failure. NA cars are prone to the issue of coolant entering the cylinders. At first it starts with missing etc and can move on to hydrolocking.

yea checked coolant, level is fine, heres the new scan results, ive changed every component dealing with the ignition. jus rescanned and it comes back with, knock sensor- no signal, and trans range switch. ive changed both knock sensors, so what could cause it to say (no signal). im getting frustrated with my car any suggestions ?

maybe a injector have had that happen on the 99 se i just put a motor in

The wiring to the rear knock sensor comes from the sensor and is an extension harness that runs over the transmission and into the wiring harness. I'd pull the passenger wheel and check that wire as it heads over the trans, through the next connector and into the harness with a multimeter to ensure good continuity. Then test the front as well.

No signal is an issue.

The trans range sensor..well..we can adjust that to get it correct or replace it. It'* located right on top of the trans toward the back.

wanna thank everyone for their input, but finally came to the solution to solve my problem. after checkeing and changing every ignition component that would cause a misfire, i took my car to a shop to have them look at it and give it a shot. they checkd everything that i checkd and said it was all good, did another compressin test and the cylinders were strong as ever, so the next thing they were gonna do was tear down the intakes and charge me $600. by me having the knowledge i have i decided to do it myself. and sure enough as i took off the pllenum, one of the coolant chambers near the throttle body was chipped badly and the gaskest around one the exhaust ports was busted. replaced everything, put it back together and WWWWAAAAAlllaa. fired right up test drove stronger than it felt at 1st. Talk about a needle in a hay stack !!!! thanks !!