Wow, I read that thread and got a couple of ideas. I'm going to check my Crank Pulley. I did the Timing Belt last year and I'm sure I torqued it correctly but I'll check it to make sure.

Is there any other way to test the coils as DIY other than ohming it out?

I guess I'll have to rent a scan tool. Any particular one that I need to pull the correct codes?

The CEL hasn't been on since I changed the plugs and wires last time.
The code showed a misfire for cylinder 3.

 

Guys, I also saw an ELM327 ScanTool on Ebay for a good price. Has anybody used one of those? I could use one around the house for the 4Runner and the Silverado. I just need to know if it will show data for the sensors I need to check like the MAF & coils and stuff.

 

No ...don't bother looking for it "under the hood" as the engine would surely know that you would look there.....its obvious that your engine is hiding from you... the only question is where is the little guy hiding? Could be anywhere...If i was your engine, where would I hide?




j/k had to join in all the fun

 

If you have a misfire in a specific cylinder then there are a few things you can do to isolate the system that is causing the misfire.

For example, if I read through this thread correctly, the code obtained before replacing the spark plugs was P0303 or misfire in cyl #3. When you get a misfire code these are the things that one must consider:

What's necessary for combustion?

• Air/fuel mixture
• Compression
• Ignition

I usually follow a simple procedure when I have a specific misfire code:

• Remove the spark plug and check for fouled or fuel soaked spark plug.
• Check the removed coil with an ohm meter and physical damage (cracks, carbon tracking, etc)
• Check the attached wire for the same (ohms, carbon tracking)

The above is by no means an all inclusive guide, it is a quick and dirty method of covering the basics. From this point you can continue by moving the spark plug in question to the #1 cylinder, for example, and the #5 coil to the #3 cylinder (obviously, you'll need to get a bit creative if working with a waste spark system). With everything back together, you can then run the engine again. This is what you would expect:

Misfire in #3: Since the coil and the spark plug original to that cylinder have been moved, then you should expect there to be a problem with compression or fuel delivery. At this point, you'd need to diagnose either of these based on the clues the spark plug gave you.

Misfire in #1: Since we knew all worked well in this cylinder before it received the #3 spark plug, then we can confidently conclude that replacing spark plugs is in order.

Misfire in #5: The only change in this cylinder was the replacement of the coil with the #3 coil. As a result, we can be quite certain that the coil is failing.

The above may seem like a lot to do at first but it does save time in the end. It allows you to quickly eliminate many options from the troubleshooting items.

Hope this helps someone. By the way, where do you drive your 4Runner 90+ miles? I'd like to make sure I stay away!

P.S. Like I mentioned before, this is for cylinder specific misfires. If you have multiple or random misfires (P0300), then you need to follow a slightly different approach. Oh, another thing that usually helps with any sort of code is the freeze frame data. This is data that is stored around the time the code was recorded. Do not make the mistake of thinking it is the data stored at the time the code occured. However, it is usually pretty close to it so it should allow you to figure out what was going on with the powertrain at the time of failure. Things such as LTFT, STFT, etc can be very useful.