So recently I, being the introductory mechanic that I am, decided it would be a good idea to take my garden hose to my engine bay in an attempt to get it cooled down and clean as it was full of nothing but grease. I got the grease out, but started having a severe misfire problem on cyl. 1 near the airbox. After a fearful night of researching the problem, I concluded that it must've been water getting in the spark plug tubes preventing them from firing. I had to drive the car to work that morning since it was my only driver and it misfired the entire way there and back before I could get a friend to open up the plugs and get compressed air blown into them. After that it was fine until about half way to home, when the misfires returned. I opened it up again the next day after work and thought he didn't put it back together so I put the tubing back in until I heard the infamous "click". Now the misfires were more minor. I wanted them gone though, so I went to my local auto shop to read the check engine light and was given the code P0300 and P0301 along with one about the Mass Air Flow Sensor as expected(my mass air flow sensor wasn't at all clean and that was something I got used to). I decided it was time to change the plugs on that cylinder since it had gone about 100k without new ones and I didn't have enough for the entire 12 plugs. I put the new plugs in and then continued to clean the MAF with a cleaner. The problem I thought was fixed until about an hour later when the misfires happened again on the same cylinder. Today I took it to the shop and it pulled the same P0300, P0301, but now instead of MAF it pulled a P0400 that said that there was exhaust recirculation. From what I can tell, the misfires don't feel existent at all in higher revs, but when I come to a stop the entire car shakes. Could it be a bad Cat thats blocking up causing my misfire? What else could it be? I really could just use some advice here. Everyone keeps telling me to ditch the car since it's hit about 202k miles, but I'm persistent to fix the problems and keep it going. Any advice at all would be loved by me. Thank you

 

Spark plugs, spark plug wires, coil pack. In that order.
Then start on the EGR.
FWIW.

 

just use the SEARCH feature for keywords 'washed engine", both here as well
as Benzworld's 210 forum.

 

Alright so after some careful driving and close examining, I found some facts.
1) The engine doesn't feel like it has a misfire when starting, however when I start driving and come to a stop. The misfires happen strongly in cylinder one and they sometimes make the car spaz a little around 3-4,000 rpm.

2) When I put in the spark plug tubes. One of them just goes in and clicks like it is supposed to. However one of them, no matter how hard I push it in, doesn't give me that simple click, but it sounds like it may be working in the starting of the engine.

If those things help in any way I'd love if you guys could give me some answers

 

It sounds like you have a bad coil pack, even a minor amount of water can cause this problem. It may have gotten in through a hairline crack etc. swap the coil pack with another on the car and see if the problem "moves" when you do so.

 

Coil packs, wires, plugs, But try with another MAF mate, we have here several cars with the same P codes and the problem is caused by a bad MAF sensor

Fabio Daniel

 

I agree with everyone else.
You pretty much have to pick a starting point and go from there (coil packs, wires, plugs, MAF). All those parts are very common parts to go out in our cars, especially with higher millage.

It will still be cheaper to fix this issue then purchasing a new car but that is up to you.

Here is a link to our site for all the ignition parts, if you need them:
AutohausAZ - Ignition

Disclaimer: Make sure to check the year and model of the vehicle before placing the order.