Skip the auto shop - Our mechanics make house calls

Q: Takes three tries for engine to start and sluggish acceleration - 1990 Mercedes Benz 300CE

asked by on

When starting the engine, I have to turn the ignition up to three times before it will start. After it has started, the acceleration is sluggish. Then after driving a while it does become a smooth ride. Also, three times within the past six months while stopped at traffic lights, the RPMs kept going down until the car quit. I replaced the spark plugs. I also thought it might be a failing oxygen sensor, but the mechanic told me that my car does not use one, but he didn’t find the problem. I really love this car and want to find the cause of this. I have been changing the oil every 3700 miles. Can you determine for me what I need to do to find my car’s problem?

A: You will need to verify the fuel injection ...

You will need to verify the fuel injection pressure regulator is not leaking down or the fuel pumps do not provide enough fuel pressure and volume through the fuel filter. The hard start may be no pressure at fuel injectors at startup and then taking a few tries to build up pressure. If the pressure is low, then isolate the system to see if the regulator or fuel pump is bad. A certified professional from YourMechanic can come to your car's location to diagnose the hard start and sluggish acceleration in order to have this corrected.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: Car won't run after running rough

Hello, from your description it sounds like you might have fuel injector that is stuck open. A stuck open fuel injector will let fuel just flow into a particular cylinder, letting raw fuel just go strait into the exhaust without...

Q: Vehicle not accelerating as it should

Hello. Thankfully the Check Engine Light came on. These issues are easier to diagnose when the engine's computer has already detected what systems are showing issues. The first step is going to be to get the vehicle scanned for diagnostic...

Q: Fast Idle does not activate when A/C Compressor engages.

The idle is not supposed to increase in speed when your compressor engages, rather the throttle plate should adjust at the same time the A/C engages to maintain the same RPM at idle. This will keep the idle the same...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...