The scenerio goes like this for my 98 ML320, 168k:

Beginning of August, no power during passing, then no starting. Indie says low fuel pressure, (1)changed out the fuel pump. Ran good for a few miles and starts and the same thing, Hard Start, no start. (2)Did the fuel filter mod, wasn't done at all previously. Ran good for a few miles and starts, then again hard start no start. (3) Changed the CPS, then a few good miles and starts, then again, hard start, no start.

What could possibly be going on? It appears to be repaired then the same symptoms!!?? It's getting very disheartening.

Thanks in advance

Sounds like you need a second opinion..starting with a fuel pressure & fuel quantity test. System shouls have 55-60psi of pressure & deliver a quart of fuel in 25 seconds.

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My plans were to take/flat bed it to a nearby(40 mile) import specialist when I get a break in my schedule. (I have a flat bed trailer) I was hoping to get some more ideas as what to look for.

Well guys, took the ML320 to the import specialist, a day later, $150 diagnostics, and $12 for the part. Tech says I won't have the intermittent start problems anymore.

So, from now on this specialist is getting the work I can't do myself. $1,000 later!!!!!

One thing he said, MB won't release software to non-dealers to help diagnose the codes.

So what is it...a check valve?

DL

fuel pump relay...$12 something