My CEL is flashing. Decoder indicates #2 cylinder is misfiring (I can feel it) and mixture is lean. Anything I can do?

 

First thing I'd check for is a vacuum leak.

 

start with the plastic tube that goes from the air filter to the intake. these are known for tearing in half. starts as a small crack, works its way into a big one.

 

Assuming the tear is upstream of the throttle body, this cannot cause a lean condition as the MAF will still correctly identify the mass of the inbound air. More likely the leak (if one exists at all) is where the intake manifold for that cylinder meets the cylinder head.

 

Thanks...I'll check that. Anyone know of an online (free) service manual for the 2001 Protege? Looking to access the intake manifold area.

 

Please be advised, any sites with "free" manuals most likely violate copyright laws and will typically be shut down in short order; better you simply buy a service manual for yourself.

The above said, AutoZone does maintain a "How-To" set of guides on their web site, complete with pictures. You might want to give that site a try.

 

Thanks, Shipo...will check Autozone site.

 

In addition to a vacuum leak, since the code is specific to to the number two cylinder:

• Check to make sure that the plug wires are seated at both ends
• Make sure that the injector is working on #2 (use a screwdriver or similar as a stethoscope and listen for a click to indicate that the injector is pulsing)
• If the injector isn't working, check to make sure that the wiring harness is plugged into it
• Try running some Seafoam through it - does a good job of cleaning up carbon deposits

 

Unless an engine has been run on 1980s vintage Mexican gasoline, there should be no significant build-up of carbon deposits; even after a couple of hundred thousand miles. For the sake of argument, even if there were carbon deposits, they wouldn't cause a lean condition in one cylinder.

 

Experience tells me different, and it is still worth checking out if a test doesn’t reveal any vacuum leaks. I just did a service on my Honda Oddysey, part of which is removing a service plate that covers a sort of ant farm of passages for the EGR system. The passages and ports to each cylinder were completely blocked with carbon buildup, and a good cleaning really smoothed out the engine. This car has no Mexican heritage that I am aware of. Seriously though carbon can still be a factor, especially if someone chooses to stretch on tune up intervals and other service - and worse if the driver tends to putt around at low rpm.

Just last year I bought a used car online. When I picked it up it exhibited symptoms of a car that needs a tune up. After I was comfortable that the there was nothing seriously wrong with the car, finished the deal and headed home. Driving on the hwy the engine still ran a little rough, so I stopped after ten miles and picked up some seafoam. I about half a can through the intake, covering the parking lot with a cloud of white exhaust smoke, and poured the rest into the full fuel tank. I then got back on the highway, dropping the trans out of overdrive and running the rpms up to 4000 or so for about two miles. The result was that the engine ran completely smooth for the rest of my 600 mile trip. It still needed a tune up, but burning the crap out of the cylinders/injectors really works.