Help me troubleshoot my car please?

Question

I got a code for a misfire on cylinder 3, The car is hesitating at idle with sudden drops in rpms.


1. I don't know what order the cylinder numbers are assigned, so can somebody explain which cylinder is cylinder number 3 counting from the drivers most side of engine, its an in-line 4 fwd configuration.

2. How can i verify that the injector is functioning, like mechanically functioning.

3. The car has GM's stupid ignition module, and sparks are sent through these metal terminals on the bottom of the module, which, when installed on the engine, is in between the two overhead valve covers and is inaccessible, so how do you check for spark since there are no wires? can i check for it with the module off of the engine? is that dangerous due to the high voltage output of it?

4. What are some other things i can probe for to try and figure what is causing the misfire on one particular cylinder.
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-The spark plugs are new and were gapped properly
-The engine in question is the GM 2.5 liter dual overhead cam inline 4 cylinder
-There is no distributor, or spark plugs wires, but instead a unit that bolts overtop the valve covers containing everything in one solid peice, it transmits electrical energy to the spark plugs via 4 metal prongs that protrude from t underneath, when installed the metal prongs are directly overhead, and in contact with the top of the spark plugs.

Answer 1

1-second from drivers side.

2-with the engine running,take a piece of rubber hose about 1 ft. long and put one open end on the injector and the other end to your ear and listen for it to tick.Put the end of the hose on the rest of the injectors to compare the sound.If all tick the same,good.If it doesn't,it could be electrical.One terminal in the connector should have power all the time.The other terminal is the ground,and is controlled by the computer.

3-The ignition module is actually the black box that the wiring harness connector plugs into.Inside the plastic "housing" is two coils.One coil fires number 1+4 plugs and the other coil fires 2+3 plugs.Sometimes what happens is,number 2 plugs will take all the spark and the misfire shows up for number 3.Inspect the housing for carbon tracks.That will be the spark not making it to the plugs.Most likely,as Cyberdude said,the housing will be the problem.

4- check the boots between the housing and the plugs.They can arc out the sides onto the head.



Final note is,the engine is either a 2.3L or 2.4L depending on the year.

Answer 2

Cylinder #3 is the third one from the front (belt side) of the engine, counting towards the transmission. Past experience with the 2.4 quad 4 engine is to just replace the module assembly along with the boots.Very common fault and repair for that particular GM ignition design.

Answer 3

This undertaking can come from the battery. If the battery does not have the cranking amps that your motor vehicle % it is going to lag. it could additionally come from the starter. at times starters ware out and start to pull.

Answer 4

Go to local Autozone and have them read the codes on ECU, they provide the service and information for free.