I just went out to my car tonight and it's idling rough and when I accelerate it seems like it wants to stall and the check engine light came on. About a month ago the check engine light came on and the code read cylinder 3 misfire but the car was running with no problems at the time. It has new plugs, wires, and fuel filter in the last 6 months so what can I do to diagnose the problem on my own?

Hello,

Check the terminals on your coil packs.
Corroded terminals haunted me for weeks.
They should be shiny clean.
If they aren't, clean them up, and take a test drive.........If you are running strong again, you need to replace whichever coilpacks have corroded terminals, as they will continue to corrrode.

Later now,
Clint

I forgot to mention I even had the coil packs replaced when I had a tune-up done. When I went out to my car later I could smell fuel or bad fumes but I'm not sure if that was caused by the rough idling. I even tried adding some Redline fuel system cleaner and that didn't help.

I have to go to work tomorrow so this isn't good.

Get the code.
May be something totally new.
Maybe a MAF sensor..... Try shooting some Carb Cleaner through the sensor.
EGR valve.... Same thing...Carb Cleaner, and working it, in and out.
Had a 2000 here that had a MAF sensor go bad..... messing with the wires proved the connections to be bad... Only cure was to replace the sensor.

Later now,
Clint

Go to autozone and get a scan. They do it for free.

Also check the battery connections. Loose/corroded battery connections wreak havoc on our cars.

What is good for cleaning the ignition coil terminals?

Steel wool or sand paper? I'm assuming sand paper.

The same happened to me time ago, and with new spark plugs, they take out every plug and there it was, dirt on one of them, solved problem.

Same prob on my dad's Marquis when I took it to Florida. Got it all tuned up for the trip then an hour after we leave to come back it idles real rough. Shops all closed but we found out the place my dad had do the plugs messed one up a little and it ended up connecting the tip to the rest of itself because the tip was bent.

Check all your wire connections as well one maybe loose.

Thanks for all your suggestions. I tried cleaning the battery terminal cables in the morning (one is completely rusted and even chipped with no metal showing at all). I'm taking it to AutoZone to get it scanned tonight when I get off work so keep an eye on this thread and I'll post the code they give me.

Anyway I need to change that battery terminal connector even if that's not the problem, how exactly do you change that metal piece connected to the terminal cable (I probably need to change the entire cable, right)?

Hello,

If your terminals are clean, don't do anything to them. I believe they have a protective coating that steel wool and sand paper will remove. If they are corroded, they need to be replaced, or cleaned on a regular basis, as they will continue to corrode. I know from experience.....
http://home.comcast.net/~crimpton/IM004406.JPG

Later now,
Clint

Ok, I went to AutoZone and the scan showed 4 codes. Multple cyclinder misfires and manufacturer fuel/air remixer? The car engine is shaking at idle and it sounds like it's going to stall.

I asked him what would cause the manufacturer fuel/air remixer problem and he said I have to take it to the dealer to get that code? Ugh..more money down the drain.

Could it be a bad air/fuel sensor on the car causing the problem (I'm not even sure if cars have one) haha?

Hello,

Give the code numbers.
We may be able to help you if we have the numbers.... AutoZone should have told you.

Later now,
Clint

He didn't even give the code numbers.

Hello,

When you get your car scanned, it displays a number for the DTC(Diagnostic Trouble Code). Pending on the scanner whether it displays a brief description of what the problem is...... When trying to diagnose a problem, you can go much farther with the DTC number, than you can with the brief description. Since scanners are different, they may all have a different description, but they will all show the same DTC number.

Later now,
Clint

When the engine is idling unplug the MAF and see what the engine does. If it smooths out then the MAF is bad if it gets worse your MAF is good.

Well I took it to a shop and the cause is a bad fuel injector. $375.00 to replace w/ labor and to clean the others. This car is getting expensive to own. I've replaced the alternator, water pump, and now a fuel injector in the last 6 months.

This is a price we pay when you have/own a car.

Perhaps, the previous owner didn't take care of the GP, so you're paying for it. At least, you have the satisfaction of knowing those parts are 'new' in your GP.

by the way used cars will cost you on upkeep. Alternator, fuel pumps injectors don't last forever. I have a link on my web page for cleaning your own injectors.

I'm well aware parts go bad and don't last forever but it seems that I'm having many problems within a short time frame so I question the overall reliability of this car at 60,000 miles. I forgot to mention I had to replace the tie rods too. Total cost in labor and parts for the last 6 months has reached $1000+. I have also spent another $750 for maintenance with a tune-up, fluid changes, and brake pads/rotors.

Oh well..maybe I'm just a cheap and poor s.o.b. but I hope it's all been worth it and she keeps running strong for a few more years until it's paid off.

Part of the problem is your paying some one to do the labor. Hense the 750. Around here the shops charge $35 per half hour with an hour minimum. Everything you've listed is easy stuff for a DIYer. Aside from the injector cleaning (yes you can DIY but only if your comfortable with tools in your hands)

Besides those things all need to be replaced on any vehicle as they age. But just think Those tie rod ends should be good for another 60k water pump should be good for long time alternator for a long time.