For those with misfire codes / problems

[ABigBadZebra]

I accidentally posted my original problem in the 2.0 section. Had a P0302 code, car was missing bad. Here's the original post:

Hey guys, here comes another!

Decided that I'm going to get rid of my Mini Cooper S and drive the wifes paid off 2000 Protege DX (1.6l Auto, 12x,xxx miles) to prepare for the possible not-so-friendly economic days ahead. She got an 07 tC after the Protege started having problems. She was ready for a new car so I just assumed the worst (tranny) and it's been sitting for about 9 months now.

So today I decided to take it for a spin. I hadn't done so myself. In the past, at idle, it was misfiring. Today, it didn't do so at idle and even around the neighborhood (under 25MPH) it was fine. But nail the gas or try to accelerate past 30MPH or so and it was misfiring like crazy.

I decided to go grab an OBD2 reader (had wanted one for a while) and I pulled P0302 off of it.

Now, this car has had some work in the past. I actually just grabbed the paperwork:

June 2005 - 87,5xx the car was overheating. Thermostat and Head gasket changed, resurfaced head. EGR valve was cleaned out.

November 2006 - 103,351 - Radiator busted. Either caused or was caused by overheating but was caught quickly. Replaced radiator.

September 2007 - 115,177 car had P0420, P0171 codes. Catalytic converter was replaced. Also found a crack in air intake boot. That was replaced as well. Air induction system was cleaned including throttle body, air intake, fuel injectors and intake valves (I'm getting this stuff right off the receipt).

In any case, I was thinking about buying the coil packs and seeing if it would be a quick repair but Autozone now has them for $98. I think I might just take it to my mechanic so they can do the diagnostics. I can do the mechanical stuff but the electronic (ignition) stuff I do not thave the knowledge or tools for. I think it may very well be cheaper to let them spend a couple hours diagnosing and then do the repairs myself.

I'm also afraid that maybe it's a more severe problem, such as a bad cylinder. Since the car has overheated twice I worry about the internals. I don't want to throw a bunch of money in parts only to find that it's something more major.

I will keep you all posted. I may at least clean the EGR valve before taking it in, but I see that many of you have general misfire codes. I need to clear mine and see if it will throw the same code. If it does, it seems that could be a good (coil) or bad (cylinder) sign.

Any additional thoughts, guys? Also, can someone link me to the EGR valve cleaning document?

Thanks!

and today I think I solved it

Ehh, I know I posted this in the wrong section. I will also post in the 1.6 section. BUT WAIT! There is a lesson to be learned. Start with the cheap stuff. I stopped by autozone after work today. I was thinking about picking up one coil so I could test. They didn't have it in stock so I decided I'd just go home and check the plugs....

...And ran back to autozone to by new plugs.

Seems my problem is fixed now. Those old ones were shot. Surprised they were still kickin at all. Gap was .090+ on all of them. I started to bend that last plug back into spec and clean it up but realized I just needed new ones. Installed the new ones, and took it for a 20 min spin with no problems. Prior to this it was acting up right away with an mid-wide open throttle. Did all that, 70+MPH.. not one glitch. I hope I haven't spoken too soon.

In any case, glad I didn't take it to the shop right away