Q: Car misses

asked by on February 02, 2016

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?
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

the wiring harness for the stereo the chords that come from the truck in the gray connector there is a pin missing what is that

Sometimes radio wiring harness' have pins that are missing on purpose due to the fact that there are more pin holes in the connector than there are wires. If this is not the case, it is possible that a wire...

Does my ECM / PCM have to be reprogram after replacing with new one?

Hi there. If you were to get an ECM (engine control module) from the dealership, the dealership will flash (program) the ECM to the VIN number to your vehicle and all of the specs. However, if you were to purchase...

Vehicle not starting.

This truck came with a three different size engines. The most common reasons for no starts are the engine timing belt is broken. The fuel pump is not pumping and would need replacement. A qualified mechanic would be able to...

Related articles

How a Car Ignition System Works
The The complicated process of a vehicle's ignition system requires precise timing on the part of the various systems involved. Starting a vehicle involves much more than just turning a key in the ignition switch; it requires each system to...
How Long Does an Ignition Relay Last?
When When trying to crank a car, you will need a few vital components to be working in order for the process to be successful. On most cars, there is an intricate network of relays and switches that allow for...
What Causes Spark Plugs to Wear Out?
Without operational spark plugs, your engine won’t run. If even just one plug were to fail, the change in functionality would...