John Major

Okay so I'm in downtown traffic trying to get to a video set on time and I downshift because this slow *** in front of me is being...well...slow. Problem is, I downshifted way to low and then the check engine light comes on. Car goes into limp mode, I stop, turn off the car for a few secs, turn it back on, everything's fine. I do notice a bit of lag from driving but I figure it's my MAF sensor which needed to be replaced anyway. Everything goes okay for the rest of the night, check engine light even goes off on it's own. Then the next morning I'm on the way to go get the video director for our next shoot and then it comes back on again and car slows down to like 30mph! At first I think it's limp mode but after I stop by Autozone and erased the codes, it comes right back on and drives horribly. It's like it lost pressure! The codes I got were, misfire on 3 or 4 different cylinders and then an EVAP leak "large" code. Don't know what the problem could be but I hope I haven't seriously damaged my engine. It comes on fine and the gears still change but like I said it barely moves over 30 mph! Just no pressure whatsoever. Friend told me it's a vacuum leak. Any suggestions? Please help!!! Below are the codes.

P0304
P0306
P0305
P0300
P0455

Cops_h8_me!

you might have popped a hose off?

what vehicle do you have? E55k?

JamE55

What video are you guys trying to shoot? Any movie stars? Pics?

Alexbenz

why don't you just take it in and get it serviced

John Major

I drive an E320.

For the other question, we just shot the new Young Jeezy/R Kelly and Young Jeezy/Keshia Cole video. I'm a casting agent.

John Major

Want to see if I can take care of it myself first. Got a mechanic coming to take a look at it but would like to know as much as possible before he gets here. Helps to compare.

jmf003

The codes match your general recollection:The bad news is, when you downshifted, you mechanically forced your engine to over rev. Unfortunately that can cause all kinds of things to break, as you'll see if you follow the links for the specific error codes.

Pretty much all you can do, I think, is put a mechanic on the job and hope for the best.

Sorry that I don't have more encouraging news but best of luck to you!

Quadcammer

Unless MB is a little crazy and forgot to add this, most manumatic cars will not allow the tranny to shift down if the revs will exceed redline.

Unless he's got a manual eclass that I don't know about.

notoriousALE

John, just PM'd you. The misfires could be almost anything but I'd bet you need to check your spark plug wells for oil, and check the valve gaskets for seeping oil. These get brittle over time and oil seeps from them, pooling in the plug well, causing havoc. Switch the plug coils over to the opposite side and see if you get misfires on those cylinders. If so you have bad coils. This is not a big deal.

jmf003

Yeah, the tranny is "supposed" to block a downshift that would over rev the engine but there are posts in various MB groups about downshift over reving happening in spite of the built-in protection. That could happen if there's momentary failure by the TCU or a set of conditions that exceed one of the boundary conditions in the TCU programming.

My original post was definitely too declarative, though. I should have included a qualifier along the lines of "might have." Sorry about that.

John Major

At the shop now. They told me I have to replace both cats! No more down shifting for me. They still didn't say anything about the EVAP leak though. Any suggestions?

John Major

CAR IS FIXED!!! Thanks for your help everyone. I have an excellent mechanic. He replaced both cats and now the car drives even better than it did before I messed it up. The best part is I only spent 400 bucks!

bzliteyear

WOW - only $400!?! ...and for BOTH!
i've seen receipts that they run $1300 EACH!!!

Alexbenz

they aftermarket cats?

MB>BMW

i spent 900 on my right side cat


is it aftermarket or MB?

Alexbenz

for that price it's got to be aftermarket unless there used maybe?????

but i've heard horrible things on aftermarket cats for the w210 so i would stay away

John Major

Well thanks for scaring me Alex. I think they're aftermarket. What stories have you heard about the aftermarket's?

MB AMG

John,

Did you see and hear the car overrev when you downshifted? I still think it's strange it could do that. Oh, how many miles do you have on your car?

Alexbenz

that they don't last too long and might give you error codes......

John Major

I dont exactly remember if it over revved but I do know it hit redline and it jerked pretty hard because of it. My MAF sensor needed to be replaced which may have something to do with it.