If your car fails emissions, the testing facility should give you a reason why. This will be your first indicator pointing you in the right direction.

Also, when was your last tune up? This in itself could fix your problems. If you've already done a tune up, then a more thorough diagnosis is in order. Have your tech check the EGR valve, Cat efficiency, O2 sensors.

Also, keep in mind that your engine has 200K miles on it. No engine last forever, and when they begin to wear significantly, they produce more emissions, and will eventually need replacing/overhaul/rebuild.

Answered by Ernest Clark (expert)
1,762 answers provided

The engine itself seems to be in good shape... I'm a diy guy and can't afford mechanics right now. I got the car for $50, so I'm trying to see if there is any tinkering I can do to get it going better. My area doesn't require emissions that's why I got the car, I was just told that it wouldn't pass last time they tried it. I'll get going on a tune up, but the person I got te car from did say something about the ecu.

Response from Lbean
2 questions asked

If the ecu as failing, you'd have drivability problems. If you haven't yet performed a tune up, start at the plugs and read them. You can search the net for pictures of all the various conditions of plugs and what they relate to. Also, I'd suggest changing the 02 sensor as well, since you don't know how old this is.

To elaborate further on your ecu, when these begin to fail, the will usually fail to send a signal to the coils and or fuel injectors telling them when and how to fire. Of course the computer can fail in other ways, but this would be the most common and obvious sign. Don't replace the computer unless you're positive it's gone bad.

Answered by Ernest Clark (expert)
1,762 answers provided

I will add my Bob's worth here, have you done a scan for any unresolved fault codes, check the engine temp sensor as well, check all the usual tune items including comps, also it will be a good idea to have the injectors check for spray patten and flow rates.

mark (mhpautos)

Answered by mhpautos (expert)
26,869 answers provided

Thanks, that gives me something to start with. Another thing is, the check engine light is not on, does that change anything?

Response from Lbean
2 questions asked

Not all codes will set a MIL, so do a scan anyway.

mark (mhpautos)

Answered by mhpautos (expert)
26,869 answers provided