I'm new to the Mazda market and have been looking at purchasing a Protege5. I found one but it runs a little funny. I found one for sale but as I mentioned the engine runs a little funny. So far the owner has done a lot to it.

So far he has replaced the catalytic converter, o2 sensors, new plugs and wires, timing belt, water pump, egr valve, and maf sensor. He said that all that needs to be replaced is the ignition coils, which is too expensive for him to fix for a car that he just going to sell.

According to him the car runs and drives fine most of the time but occasionally, it will just not want to run correctly, and will stop firing on one or two cylinders which does sound like the coils to me.

I'm worrying that there might be something serious wrong with the car so I was hoping someone could point me in the right direction in this. I don't want to end up sinking $2,000 into a car that I just bought.

Thanks in advance, Travis

 

Could be coils. Also a symptom of a bad IAT sensor. These rarely go, but do exactly that when they do go. Is there a check engine light?

 

I don't think that the check engine light is on. What is the IAT sensor? Is it Intake Air Temperature senor, and where would that be? I'm thinking it would be on the intake manifold somewhere.

 

Yes, intake air temperature. It is plugged into the intake tubing. If you start at the air box, follow the tubing up towards the engine and you will find it (little round, black plug) between the MAF and intake manifold. It just presses into the tubing, no tools.

 

Very nice, that should be easy, and I'll probably check the tubing around it. Someone suggested it and although it probably wouldn't cause the problem it doesn't hurt to check.

Just found it at a parts dealer for $44. A little more than I was hoping but that's how small parts go...

 

Alright, so I got the car and stopped by the auto parts store and got some lucas injector cleaner. I put that in and after about 10 miles of driving the CEL shut off. Possibly stuck injector? It makes sense to me...