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Old 02-02-2004, 10:42 PM
osmosis osmosis is offline
Registered User
Join Date: Feb 2004
Location: Florida
Posts: 17
Question 98 ML 320 low engine power ??

Thanks all for the great info here

I have a 98 320 with 91K miles.

It's had all the warantee work that everyone else has described +some. From the balancer to the fuel pump to the window switches, dash that fell apart, dash swtches that just fell out. Turn signal / high beam switch fell out of column. Computer "forgot" all the keys. Sunroof stuck etc.

And the brake job after brake job, after brake job.

The brakes amaze me just because I have never had a vehicle that got less than 90k miles on brakes ( including 3 corvettes ) so I'm not a "brake diver" but the ML sure eats em.

OK now the problem. I have had some CEL issues. I tested and got the "fuel bank 2 mis -. I replaced the plugs, and cleaned the MAF sensor inside and out with high quality electronics cleaner and cleaned the EGR valve tube and throttle plate with a spray fuel injector intake cleaner. All is well in the CEL world. ( at this minute ) ( 1000 miles, and 3 fillups later)

However the vehicle seems to lack power from about 30 MPH to 60+. It just seems to take forever to accelerate. Under no load the engine will only rev to 4200 then it appears that a rev limiter kicks in and the engine will not rev any higher. I slowly bring up the rpm till it gets to 4200 and then it "misses" and stays at 4200. (valve float ??) or a rev limiter?? I'm OK with that if the engine does have a rev limiter.

Now under load from a dead stop , smash the gas and the engine will go to about 5500 in drive and then shift up through the gears. Shifting seems normal, however from about 55, "kick down" to accelerate doesn't seem to work correctly. It just seems to have a poor power curve. Our 2001 Isuzu trooper with the v6 has MUCH better acceleration from both a stop and for "passing"

None of the CEL codes have indicated the O2 sensors.

Does anyone have any 0-60 times that I can compare to, as this would tell me immediatly if i'm in the ballpark proformance wise, of driving a slug in need of repair.

I get 22.9 MPG on the highway as averaged by the onboard computer, so it appears to be running fine, and doesn't seem to miss at an idle.

I am installing the front Monroe Reflex shocks ($41.00 ea) to improve the ride a little when hitting road expansion joints. And installing drilled rotors ( I drive through tons of standing water ) and the new Wagner Thermo Quiet pads. I figure with how I go through stock pads and rotors, how could these possibly perform worse ?? and for less than $200.00 per axle, I can burn through a lot of these brakes before I touch the dealer parts cost.

Anyone use the valvoline Dot 4+ Synthetic break fluid. ??

Sorry , big post. Again thanks for all the good info.

98 ML 320
2001 Isuzu Trooper
2003 Vette zo6
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