Sudden Misfire and power loss... but no Codes!

[tinovittee]

Hi Guys! So I'm driving down the N12 on Saturday night cruising at about 100kph, no problems. As soon as I got up to about 100kph, the car starts sounding like an old diesel, with no power. I pulled over, switched off, started again and the engine was running smooth. I pulled off gently, got back up to 110kph and the same thing happens. switched off, started again, managed drive back home all the way at about 90-100kph. No warning lights....

No Idea what it could be. Did some reading but the list of possible causes seems to me a lengthy 1! MAF, coils, plugs, water in the fuel tank, Throttle Position Sensor, Cam position sensor...etc. which of these would trigger the engine/EML lights and which wouldn't?

Also, it just came back from an oil change...

Thanks in advance for your help guys!!

 

[Dippies]

Mmm mite be something simple like a dead sparkplug.

 

[Fat Tom]

mine is going in on wednesday for the same thing. error codes i logged said something to do with the fuel pump....

 

[Xeqtr]

mine is going in on wednesday for the same thing. error codes i logged said something to do with the fuel pump....

Could be 02 sensor, or coils going... nothing serious im sure

 

[tinovittee]

Thanks guys. If it was a plug, or coil or O2 sensor... would I get an error light?
Based on a previous experience with my folks' C-Class, does seem like a dying plug now that you mention it... same symptoms.

Tom, did your fuel pump issue trigger a warning light...? did you do a fault code check?

My car went in this morning, but it's an intermittent problem so I'm guessing it will be hard to find...

 

[Xeqtr]

Thanks guys. If it was a plug, or coil or O2 sensor... would I get an error light?
Based on a previous experience with my folks' C-Class, does seem like a dying plug now that you mention it... same symptoms.

Tom, did your fuel pump issue trigger a warning light...? did you do a fault code check?

My car went in this morning, but it's an intermittent problem so I'm guessing it will be hard to find...

I did not get error lights, just error codes bro!

 

[tinovittee]

oh ok cool... so it's possible to have a problem and have an error code but not have the engine/EML light come on. Good to know... :thumbs:

 

[tinovittee]

So, got my car back from the dealer yesterday and there were no fault codes... so they didn't check anything else :argh: Just reset the errors and that was it. They said to drive the car until it happens again and then bring it back... :nonono: Was planning to go to Durbs with it this weekend... but don't want to get stuck, or have to do 90kph the whole way there...

 

[Die_Miek]

could be a vacuum leak as well.
i had a dead plug on my e46 2 weeks ago, fault that logged was "misfire on cylinder 1 with fuel cut off" so the ecu cut off fuel supply to that cylinder when it wasn't firing.

 

[tinovittee]

The tricky thing is trying to determine what would cause a problem, without causing a fault code? The fuel pump etc didn't trigger any error codes...

 

[akash]

So, got my car back from the dealer yesterday and there were no fault codes... so they didn't check anything else :argh: Just reset the errors and that was it. They said to drive the car until it happens again and then bring it back... :nonono: Was planning to go to Durbs with it this weekend... but don't want to get stuck, or have to do 90kph the whole way there...

The fools should have driven the car at the speed that the error was kicking in at :nonono:

Common sense.

 

[Kyle]

Sounds like a fuel pump issue to me,

If it was a dead spark plug it would surely do this all the time and not just over 100kph?

 

[tinovittee]

I had the same issue with my folks' Merc... when we eventually took the spark plug out, it was broken! but it used to only cause problems intermittently. when it made contact, the car ran fine, but sometimes there would be a misfire, until eventually the plug failed completely.

Spoke to my friend that works at South East Auto so he's having a look at it for me today at the dealer... hope he finds the issue. He reckons it could be one of the coils dyng... the diagnostics said the fuel pump is 100z... dunno if that can be trusted though :dunno:

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So, got my car back from the dealer yesterday and there were no fault codes... so they didn't check anything else :argh: Just reset the errors and that was it. They said to drive the car until it happens again and then bring it back... :nonono: Was planning to go to Durbs with it this weekend... but don't want to get stuck, or have to do 90kph the whole way there...

The fools should have driven the car at the speed that the error was kicking in at :nonono:

Common sense.

Commone sense is far from common these days hey... :nonono: