tdog

My 2000 E55 with 94K is experiencing a problem with bucking and surging. The first time it happened I was sitting at a stop sign took a left punched it and it bucked and surged. The second time I was on a hill took a right punched it and it did the same thing. The other day I took advantage of an opening in traffic punched it and it did it again. Yesterday morning while getting on the freeway I punched it and it happened. After searching the archives here I think I might have a problem with the splash bowl in the tank, fuel filter or the MAF. Looking at the PO records it look like the fuel filter, spark plugs and MAF were replaced at 65K along with an injector cleaning all performed at the dealer. Please share your thoughts.
Thank in advance.
Tdog

C43AMG

Wires ? Seems like everything else is done.What do your air filters look like ?

mikekuriger

clean the MAF

tdog

I did the soft reset and the problem still exists. It only happens when I go WOT, it starts around 3500 rpms. I also tried all of the transmission modes W/S with and without the ESP. Could it be the kick down switch? I'll look at the air filter and find the DIY for cleaning the MAF. If the MAF was dirty would the check engine light come on? To date it hasn't so I don't understand how this could be happening without the check engine light coming on.

Thanks
Tdog

saintz

I would consider a new TPS if you're having issues with WOT and hitting the kickdown switch. After you go WOT, does your cruise control still work?

MAF can be dirty and not throw a CEL. It's old enough it could be bad again.

armaniE55

+1 or you can remove the MAF and test highly doubt it.. Might be something the dealer can diagnose.

GL

keep us posted

Armani

ejsheltra

Try crank positioning sensor at top rear of motor. Its about $40 bucks and ten minutes of your time. These periodically go bad and can cause some of what you are dealing with. Anyway its cheap enough insurance to do. Is the battery fully charged as well. Gel batteries are good typically for 6-9 years depending on service load and standards are 4-6 depending on same. These motors require alot of juice to run properly. Just some other thoughts.

tdog

A full tank of gas cured the problem.
Thanks for the support!
Tdog

MBFLO

now thats a cheap fix ...

Interplexor

I don't think it solved the problem, so much as masked a larger issue. Check your fuel filter, fuel pressure regulator. Possibly you have a weak fuel pump...

AMS Performance

pour 1-2 cans of seafoam in your gas tank and run the car hard for the whole tank, see if that gets rid of most of the issues. Could be a dirty clogged injector based on what you are describing. Seafoam should help alleviate the problem but interplexor is correct... it is merely masking the problem, not solving it, once tanks gets low again problem will resurface.

MBFLO

i wonder if the sea foam would help get the hiccups out of my car as it gets this weird surging at a stop light/ complete stop every once in a while as if im giving it gas but my foot is on the brake. somtimes i put it in nuetral ,give it gas and it clears but does it again after a day or two .. and no CEL ..peterAMg said it could be egr valve but havnt really checked it yet

sorry op not tryin to jak yer thread .

armaniE55

I have a fix for you... Happen to me recently...problem fix.. Check out new post "Techron", I'll put one up for you

Armani

AMS Performance

Techron does roughly the same thing but seafoam is extremely concentrated and should be more effective. Using Chevron gas really does keep the engine running cleaner over the long run (you still gotta mash the gas every once in a while to get all the carbon out).

Also, just b/c you replaced the MAS 30k+ ago does not mean its not bad. The most common side effect of bad MAS is rough & jerky shifting with inconsistent unsmooth throttle acceleration. If you are cleaning the MAS, how are you doing it? If you are doing it with CRC spray it may make the matters worse. 91% isopropyl & q-tips are the optimum way of gently cleaning it (remember to clean the plug contacts as well, not just the sensor). Hope that helps.

tdog

I’m using Chevron gas already so adding Techron at the next fill will be a no brainer. I’ll also be able to see if the problem still exists.
Thanks again for the support!
Tdog

telpsicorei

I have the same issue with my tank. I still dont know what it is, but i cannot go past 1/4 tank or else my fuel pump starves for gas. I ended up pulling the tank and trying to look around in it, but found only a few pieces of my filler neck (previous owner i guess liked to ram the nozzle into the tank). Tank was otherwise perfectly clean. I tried to look at the splash bowl, but it was to hard to see anything. I may have something still lodged in my spashbowl, but i dont think i want to take out my tank again to figure it out-- once was bad enough. PLUS i called the dealer and they said that the tank is not serviceable, so a replacement of the tank was like 800$ in parts.