Hi!
So here's my problem...
The car (a 2001 Cavalier, 2.2L OHV engine) was having power problems. It would barely make it up a hill. It started misfiring (I couldn't hear it misfiring, but it was reading code P0300 random/multiple cylinder misfire. Replaced both ignition coils, the wires, and plugs (gapped correctly), and fuel filter. Then, I cut the exhaust before the cat because of a suspicion that the cat may be blocked. Compression had a low reading on Cyl # 3, and no compression on Cyl # 4, so I replaced the head gasket, oil, and coolant, then re-read compression, and all cylinders read 80. After all of this, it was still running the same (no power, misfires, etc.). It would rev up just fine in neutral, but put it in gear and put it to the floor and the RPMs wouldn't even move. (It's an automatic). Brakes are not binding, it will roll just fine.
So I thought of trying to clean the injectors by running a bunch of injector cleaner through them, so I took the fuel rail off, drained all the gas, and poured a little injector cleaner in the rail and mixed it around. I also poured a little down the fuel supply line when I disconnected it from the rail. Then I reconnected everything, started it, and it started then started studdering, wouldn't stay running, and now I cannot start it at all, it's like no fuel gets to the intake. When I put Ether in the throttle body,it would fire up. I took the fuel rail back off and dumped out all the gas (to clear out any concentrated injector cleaner that may be in there), and put about 3 gallons of gas in the tank (just in case it by chance ran out of gas, because it was getting low). It won't start. The fuel pump does work, I can hear it when I turn the key.

Could putting that injector cleaner in the rail have damaged something? And any ideas of anything else I can check to get this car running right after everything I've tried?

Thanks!

have you pulled your plugs yet? never a good idea to clean your injectors that way cause it can hydrolock the engine causing bent pusrods etc, pull your plugs and make sure your cylinders are drained. also pressure check your fuel supply should be a port on the injector rail and read somewhere betweet 30-38 psi also the misfire sounds like a bad or extremely weak ignition control module (icm) try some of these things and let me know if it helps


MEAN & GREEN.

I can't say whether it's true or not, but I've heard from a reputable source that using too much fuel injector cleaner can damage the coil inside the fuel injector. By dumping it right in you may have destroyed them (if the above statement is true.) If the engine will run with ether then I'd check the fuel pressure first. Though the pump may be working, you may not be getting adequate pressure, and that would explain some of the issues you described first in your post. If you're getting proper pressure, then you may want to replace the injectors themselves.

Sounds like youre motor is crappin out. How many miles on it?.

have you checked the fuel pressure?
the fuel pressure reg may be dead or dying