I have a 95 E20 wagon / It is now revving /surging the engine up and down like ur pumping gas and letting off gas I am getting a code 10 from the DTC Diagnostic Module Last week I had a radiator light problem now that has gone away

You might try a search on the OVP, sounds suspicious. I do not know about the codes.
Ed

When my car did that about 6 mos ago it was the MAS (Mass Air Sensor) which code 10 implies. See below. Codes from somebody else, from another thread, a long time ago.


Emissions - Using Built-in Diagnostic Module
1 No Fault Found
2 Heated oxygen sensor faulty
3 Lambda control faulty
4 Air injection system faulty hot film mass air flow sensor with hot wire
5 Exhaust gas recirculation faulty
6 Idle speed control faulty
7 Ignition system faulty
8 Engine coolant temperature sensor open circuit
9 Intake air temperature sensor, open circuit
10 Voltage at mass air sensor too high/low
11 Tn-signal (rpm signal ) at engine control module faulty
12 Heated oxygen sensor heater circuit open or circuit short
15 Injector, cylinder 2
16 Closed throttle position information faulty
17 Data exchange malfunction between individual control module
18 Adjustable camshaft timing solenoid circuit open or circuit short
19 Injectors circuit open or circuit short emission control module adaptation in engine
control module at limit
20 Vehicle speed signal not present
21 Purge switchover valve circuit open or circuit short
22 Crankshaft position sensor signal faulty
23 Intake manifold pressure (in base module pressure sensor-) with engine running too
high/low.
24 Starter ring gear segments and /or crankshaft position sensor faulty
25 Knock sensors or engine control module faulty
26 Upshift delay faulty
27 Not used
28 Engine coolant temperature sensor (engine coolant temperature change monitor )
44 Not used
45 Fuel safety shut-off electronic accelerator or cruise control active
46 Resonance intake manifold switchover valve
47 Not used
48 Not used
49 Voltage supply at engine control module 8v
50 Engine control module

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dtf
1994 E320 Wagon (Died @ 308,669 miles)
1995 E300 Diesel (228,000)
1999 E300 Turbodiesel ( died @ 255,000)
2006 Toyota Tundra SR5 AC 4X4 (115,000 miles) rusted frame - sold to chop shop
2011 Audi A4 Avant (165,000 miles) Seized engine - donated to Salvation Army
BMW 330 xi 6 speed manual (175,034 miles)
2014 E350 4Matic Wagon 128,000 miles
2018 Dodge Ram 21,000 miles

Where is this mass air thing and how and how much to replace? OVP i just replaced that 4 months ago

The mass air thing is the item between the intake and the air box with a wire attached to it coming from the battery area. It has a round connector that twists off. Remove it while its running and see if this solves the problem, If it does then most likely the mass air meter needs replacement. IF it still does it after replacement, then I would say your wiring harness is suspect if it has never been replaced. Do a search on this forum and you will find plenty about it including stuff I have posted as well.
Chris

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94 E320 with:
18" ///AMG Monoblock II's,AMG Gen II front bumper, H&R spings,500E sway bar, Bilstein sports, Eisemann Exhst, K&N,E500 Headlamps, Crystal Clear Corners, Avantgard Grill ...and more stuff to come! oh yeah 241k miles!!


My Car WOO HOO...... Now SOLD
New car.... 2001 Jaguar XJR!!!!

I unplugged the mass air circular switch out and engine still is revving (not missing) just revving between 5000 and 10000 rpm up and down and it does it irregularly like when its cold or hot /at a stop light sometimes and in the garage usually after driving it around. Engine temp is fine/seems to be a tad worse in gas mileage/ a really strong chemical smell halfway between gas exhaust and something chemical. Replace ovp relay a few months ago/ has 188,000 bought it 1 year ago w/ 159,000 miles. The DTC is pulling a code 10 which is the mass air flow issue. HELP