Okay so heres the deal. For a while now my car has had a little bit of a rough idle and the tranny was doing some ****ed up things and was also causing a bit of a vibration through the drive train. Well i had a used tranny and converter that were given to me that i attempted to swap out in my garage. All i got off was the drive shaft out of the car and the bolts that attach to the tail shaft. Got stuck when i tried to take out the converter bolts and just gave up, put it all back together and said its going to a mechanics to have this done. I decide im going to take it out for a final spin before it goes to the mechanic so i take it out for a couple hours its running pretty normal some problems but as good as ever. Well im driving home and get within a 2 min drive of my house and i hear this massive back fire and am like wtf. Then i hear it again, then the engine stumbles, and this continues all the way to my house of which i just barely get it home. Talking to a buddy about it he says his dad had the same thing happen and his coil just went out. I figure that could make sense so i grabbed a new coil. Car starts up fine even drive down the street and around the corner but then starts stumbling and backfiring.

So now im at a loss. Since the engine is running most of the cylinders must be okay, and since its backfiring i know its getting fuel which makes me think 3 different things.

Could either be A) timing....B) ignition related as something isnt getting a spark C) an intake valve isnt working.

I dont think its timing because the car wouldnt have run fine for 2 hours then took a crap. I dont think its a spark plug not firing because ive had that before and this doesnt feel like its just dropping a cylinder.

Which leaves me at possibly one cylinder just isnt getting any air? The other anomoly is when i went to test the new coil my tack had stopped working? Does anyone have any ideas as to what it could be. Also how can i tell if i have a sticking or stuck intake valve can i just pull off the valve cover and will it be visually obvious?

 

You may be able to see a sticking valve that way. I would use a vacuum gauge to try and diagnose that thou.

 

You could perform a power balance test to identify the weak/dead cylinder(s), then analyze the cylinder(s) closely, from the ignition to the valve train, injector flows, vacuum leakage, check valve lifts, and test compression.