Replaced cataylic convertor, that wasnt the problem!
so as my catylic convertor was rattling i got it replaced, i was having a problem with my 1998 ml 320, of driving properly, it would just keep jerking. rpm would go up and down, so i toke apart the MAF and cleaned it out and that isnt the problem eitherr, as i was driving today, my gas tank was getting to Empty, the truck started to jerk a lot then it is when its on a full tank, when i got gas it jerks once and a while but not all the time, as i was getting closer to E it was doing it the whole time. i had to turn my emerency lights on, i felt pretty stupid driving as my truck kept jerking and moving very slowy, so what is the problem? could it be the fuel pump?
help plzz
Why would you replace the very expensive CAT without a proper diagnosis in the first place? Who advised the MAF cleaning and on what basis? Besides, did you post the problem here first? Since you have a lot of money to spare, take the truck to a MB shop for proper diagnosis, then proceed with fixing the problem wherever you want - though if I were you I'd have a MB shop do it. The reason I say this is because the diagnosis for a jerking vehicles falls under the category of Miscellaneous - could fill a good 200page book - there are plenty of reasons for that kind of reaction. Get the codes out first, just as a guide, then proceed cautiously.
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1989 300ZXT - mine
A pair of running shoes
A 18Hp lawn mower
2 Mountain Bikes
350Z - will be mine when @ 300+HP and 3-Car Garage
It sounds to me as if you have been driving the truck on near empty and all the sediments that normally reside at the bottom of the tank have come up and blocked your injectors in some way.
You may have to have your injectors cleaned and then perhaps change your fuel filter.
You'd better hope that your fuel pump has not been weakened too by being made to pump that much harder to send the same amount of fuel through the blocked injectors and possibly dirty fuel filter.
I would start by doing as Darkmann says above and get the codes read.
As for the MAF cleaning it may not necessarily work so you may need a new one. But again get the codes read first.
Bad fuel pump is not going to trigger any codes.
From the description of jerking with low fuel I would suspect the fuel pump flapper to not hold. This vehicle is having tricky fuel pump. It is not placed in the lowest point of the tank and to get the fuel that is below pump level it is using returning fuel venturi effect to suck the fuel into the pump sleeve, where the actual pump can suck it. The sleeve is having flapper valve that when malfunction lets the fuel drain out of sleeve, keeping the pump dry with few gallons in the tank.
If the truck shows no codes, hook up pressure gauge to the fuel rail.
Linear Mode
