Hi guys,
Am new here and have a problem I cant figure out. My son has a 1999 Camaro V-6. It will start. Will have a slight mis to it while idle. No big deal. Once you throw it in gear and take off, no power at all. We got it to 10 mph almost floored. Ok, so started checking things. Fuel pressure was at 43 psi and specs call it between 50-55. I dont think 7 lbs is going to make all that much of a difference. Shut car off and watch fuel pressure. Stayed steady. My son wanted to change injectors anyway so we did that. Still the same. Pull coil packs off and checked the secondary resistance and all 3 were the same. Pulled the ignition module and brought to advanced auto and they said it was good. All new plugs and wires. Now tonight, I tapped on the MAF sensor and nothing happened. Disconnected MAF and NO CHANGE IN MOTOR. I thought "Ah HA!" Changed MAF and still friggin doing it. The check engine does come on and it reads a P0303 cylinder #1 misfire. I thought, "ok". So I unplugged the spark plug wire to #1 and it shuttered. Good deal I thought. I unplugged the injector to that same cylinder. Again, it shuttered. I checked all the cylinders the same way. I cannot figure out what in the hell is going on with this car. Any ideas would be greatly appreciated. I really am suspected the motor may be gone. We did a compression test and all cylinders were within 10 lbs of each other. I dont understand it

 

I would do a exhaust back pressure test. You could have a pluged Cat/Exhaust. Also the combination of a miss fire and low fuel pressure, while not too bad at idle, could be failing as soon as you put a load on it. If one of your coils is carbon tracking internally it would not show up on a OHMs test. You need a tester that will put a load on the coil like this one. 90§ Inline Ignition Spark Checker

You can also clear the codes and swap coils and see is the miss fire follows.

 

i got a 2004 dodge ram hemi that done that same stupid stuff to me it ended up being the o2 sensors were bad and was dumping it full of fuel dont know how the camaro works but a dodge ram has 4 02 sensors the front 2 determin how much fuel to give it and when they go out the computer just dumps fuel to it because it thinks its lean and that will lead to a misfire code to show..

 

First off, PO303 is cylinder #3 misfire, not #1. I'm not surprised the engine shuddered when disconnecting #1. Check the #3 cylinder the same way. Inspect the plug wire and boot, look for a crack or split with a gray (burned) area around it. Also give the wire a sniff test to see if it has an electrical burn smell, it shouldn't. #3 could be shorting to ground, which will make that cylinder pour raw fuel out the exhaust, and cause the cat converter to glow red (check to see if the cat glows). Needless to say, an engine running on 5 cylinders isn't all that peppy! If the car hasn't received one, a tune up with new plugs and wires won't hurt, and might even take care of your problem.

 

I'd be checking for a bad converter that is causing major constipation. Loosen the nuts that hold the y-pipe to the manifolds and take ot for a short test drive. It'll be noisy but you'll see if the exhaust system is the problem.

 

Checking your wires actually is a safe bet, you never mentioned when the last tune up was either. Like 69 stated if a certain cylinder isnt firing it can dump fuel through the exhaust valve and cause the cat to get very very hot (dont touch it )

 

A bad/clogged cat converter isn't going to trip a cylinder specific misfire code. I wouldn't bother farting around with the exhaust just yet.

 

Your advice is too simple and to the point, and will probably ignored. lol
Many seem to like to go for the gusto, and first attempt the hardest and most unlikely solution, like tearing into the exhaust, and when totally frustrated attempt the obvious and fix the misfire.

 

Its funny when I read these post I try to imagine what the car is doing based on what the people are typing. To me a plugged Cat feels nothing like a direct ignition system dropping a coil. It would have to be droping the whole coil cause just one cylinder would not be enough to make the car undrivable. If it is the miss that is causing ther issue the car would be sputtering doing the dom dom dom and jerking on acceleration. Where a plugged cat may have a rough idle but does not feel like a miss at all. There was no mension of that so I assumed Cat first. For all we know it cold have jumped the timing chain.

After a read 69 post in my head I thinking thats different syptoms but again that is based on what someone typed, reality check for me is when you got codes fix them first and truth be told when your fuel pressure is 20% under spec that can have a huge effect on how the car runs. I would ask How low does it drop when its working hard under load?

The process to check back perssure is remove any upstream O2 sensor and start car for 15 seconds. I can do that on my 96 faster then I can check a single spark plug. Since it is such a easy check it would be one of the first checks I did along with vacuum and fuel pressure. Plugged Cat can cause plugs to carbon up then again a miss firing cylinder can cause a Cat to plug up.

To the original poster, Never pull a plug wire, With 80,000 volt coil the juice needs to go somewhere and it will arc internally if it can not externally. A single "jump like that can cause a carbon trail, in the future the spark will follow the carbon (that is where the term Carbon tracking comes from). These coils will work under light loads and pass any test that does not require high voltage (This will not show up on a Ohms meter.). The tester I posted earlier if for a test that will put a load on the coil.

 

Fix the misfire, sure, but I don't see how a misfire on one cylinder will cause the situation where the car barely hits 10 mph with the throttle floored.