Q: Car misses

asked by on

The car misses even the the compression and leak-down test are good.

If you have went as far to do compression and leak down, I’ll assume the problem is not obvious. After those tests, you can be almost sure the mechanical components of the engine are good. Is it a random misfire or one cylinder? Some problems that would affect all would be a bad ignition coil. Spray a mist of water to check for voltage leaks. Load the coil by pulling a wire ½ off a plug. Carefully inspect the distributor cap for carbon tracking. Check each plug for the same. Crankshaft position sensors are common to fail completely on these engines, however, sometimes they will put out a “noisy” signal to the PCM. Check it with a lab scope. I would also perform an injector balance test. Finally, check fuel pressure, vacuum leaks, or clogged exhaust. If you need assistance, a qualified mechanic from YourMechanic can come out and diagnose your car’s misfiring issue.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 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

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Brake noise

Hi there! Noise when braking usually indicates that there is low friction material. There is a little noise maker that will begin to scrape the rotor when the pad level becomes low. This noise serves as an audible warning to...

Q: My car won't start. The odometer reads: NO BUS.

The error code "no bus" means the PCMS are not communicating with each other. Likely one of them has gone bad, or there is a bad connection. You can do further testing on them using a multimeter. This will require...

Q: My 2001 ford expedition has been shaking over 65 mph ive changed the ball joints inner and outer ties rod ends brakes and rotor hu

The shocks may be worn out and when you get to the higher speeds there is a normal tire vibration from road surface and the shocks should keep the tires in contact with the road. Have shocks replaced if they...

Related articles

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...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.