I have problems with my 1999 mercedes-benz ML320. minutes after ignition, when driving at low speed or high speed acceleration note failure. push the accelerator pedal fully and have no adequate response. the engine feels very unstable. then put the engine off, once I turn on the engine and the fault goes away but only for a few minutes, then return the problem!

Harvey N Tawatao

• 3854 Answers
• Posted on Jul 07, 2009

SOURCE: my 2005 ford explorer has acceleration problems

You may have a problem with your MAP sensor. The Manifold Absolute Pressure (MAP) sensor signal is electrically used in a similar way to the use of Mass Air Flow (MAF) sensor signal (although internally it is built differently). It takes a 5 volt signal from the computer, and returns a lower direct current signal in accordance with the vacuum in the engine. A higher output voltage means lower engine vacuum (which means more air flow is occurring), which is then calculated as “more fuel is needed”. Lower output signal indicates higher engine vacuum (which means lower air flow), which requires less fuel. 
It's not just fuel control though. The MAP sensor signal gives the computer a dynamic indication of engine load. The computer then uses this data to control not only fuel injection, but also gear shift and cylinder ignition timing. In some cases it is even used to calculate changes in barometric pressure, to automatically adjust for different altitudes.

The Mass Air Flow (MAF) sensor helps the computer to calculate the flow and mass of the air entering the engine. It does that by measuring the cooling effect of air flow over a heated wire element. The electronic circuit inside the sensor attempts to keep the sensor at a fixed temp.
When it is cooled more by an increased air flow, more current is needed to maintain a constant temperature. The increase in current is converted into a signal to the computer. In most cars this signal would be a high frequency signal. Not as high as a radio wave, but much faster changing than the (relatively) slow frequency of the Oxygen sensor.
During low air flow rates, such as at engine idle, the MAF sensor produces a lower frequency signal. During high air flow rates, such as at wide open throttle-road load, the MAF sensor increases the frequency. The control module then converts these frequencies into their corresponding Grams-Per-Second values.

The MAP or Manifold Absolute Pressure Sensor is a little though expensive device installed in your air intake hose or piping, or installed on the firewall and connected to the manifold with a thin hose. It has 5 or 12 Volts coming in, and it simply senses the vacuum in the manifold and attenuates (reduces, weakens) this incoming voltage by a certain factor. In other words it reduces the voltage in the range of 15% to 60% of the supply voltage (depending on the car's design these numbers will vary), and this varying (but non-pulsing) signal goes to the computer. Too much attenuation kills the engine, it will simply shut off. Yet if you control it correctly you can lean down the mixture from the stoichiometric (a big word that simply means “balance of ingredients”) which is factory set at 14.7:1 (14.7 parts of air to 1 part gasoline) – down to 20:1, maybe even 50:1 or 100:1.
Good luck and hope this helps, in short: you may have a bad MAP sensor and may needs to be replaced.

SOURCE: mercedes ml320 - hear noise sounding like springs recoil

our shop work on alot of ml320 the noise you are describing is a bushing in the rear suspension,on the torque bar.

SOURCE: Ford F350, 7.3 powerstroke, accelerating from 0-60

does it have acentre bearing in the tail shaft ?if so ,fhat is more than likely the problem .also check that all the tail shaft yoke s are in line,they only have to be 1 spline out togive those symptoms ,a rumble ,is definatly coming from the driveline

SOURCE: Hyundai i30 Diesel automatic won't accelerate above idle at light

DOES THE ENGINE MIL WARNING LIGHT COME ON? WITH OUT MORE INFO YOU NEED TO CHECK MOTOR ON A CODE READER FOR STORED FAULTS, CHECK ALL AIR LINES TO EMMISION CONTROL, , SOUNDS LIKE YOU HAVE GONE INTO SAFE MODE, A SPLIT OR LEAKING PIPE ON THE INTERCOOLER IS A COMON FAULT ON THESE, IF YOU SWITCH ENGINE OF AND BACK ON QUICKLY WITH MOTOR RUNNING WITH OUT STALLING MOTOR AND IT CLEARS THEN IT IS PROBERLY THE SAFE MODE CUTING IN MEANING A FAULT HAS BEEN SEEN BY PCM

Testimonial: "Thanks.Didn't notice any engine lights came on. I had a problem free day today, but if it happens again will check warnings and PCM computer check"

SOURCE: When first driving, I hear a high pitched

I have the exact same problem, however reversed. My whistling sound stops when I accelerate and starts when my foot is off the accelerator. Frustrates me and am afraid to have it looked at for fear of the cost of fixing this problem. Have you since discovered what the problem is or was?