Q: P0300 code, misfiring on a '06 Hmamer H3
06 Hammer H3, 87,000 miles, inline 5 engine. Got the P0300, multiple misifres. I've changed the sparkplug, coil pack, VVT solenoid, cleaned the throttle body and MAF. I don't know what else to do. Any ideas?
Recommended Services
| Check Engine Light is on Inspection | $94.99 - $114.99 | Get a Quote |
Those things are notorious for having fuel injection problems. GM made them with cheap plastic and the fuel injection parts, so when they get to be older, after 10 years old, the plastic cracks, leaks, and gets multiple misfires. That’s a typical problem with that.
It can be hard to diagnose the P0300 code yourself. It can easily be the injection system and that is a very complex system. You don’t want to take the whole engine apart yourself, which you’d have to do to get to the injection system. My recommendation would be to have a professional technician, diagnose Check Engine Light for you and make the necessary repairs.
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
What others are asking
How do the illuminated entry and exit lights work?
Your car is equipped with illuminated entrance and exit lights. These provide you with better visibility when getting in or out of the car during low light situations. When you use the key or the remote to unlock a door,...
Clutch pedal not returning
The clutch in your car is hydraulic. The weight from your leg when you push the clutch pedal transfers to the clutch master cylinder. It forces fluid through a hose to the slave cylinder. It in turn pushes a lever,...
tailgate lock not working
Hey there. Thanks for writing in about your tailgate lock on the 2006 Ford F-150. If your tailgate uses a manual key-operated locking system (https://www.yourmechanic.com/article/symptoms-of-a-bad-or-failing-tailgate-lock-cylinder), it's quite possible that your lock is stuck or frozen due to debris, gunk or...
How do I get to the subwoofer to replace it?
The subwoofer on your car is buried underneath a rear cover with four bolts holding it in place. To access the rear subwoofer and the bolts holding it, you will need to move the seats forward and remove the rear...
Engine doesn't start but lights power on - 1986 Ford LTD Crown Victoria
You're thinking in the rigt direction! Something in the electrical power path to the starter motor is malfunctioning: starter solenoid or starter motor itself, ignition switch (https://www.yourmechanic.com/services/ignition-switch-replacement), or wiring to either of these components. A professional mechanic, like YourMechanic, can...
My car cranks but won't start.
Hello, thanks for writing in about your 2002 Pontiac Grand AM. There are several possible causes for a vehicle to not start. There could be a fuel supply problem, an ignition problem, or even a failed sensor. For an issue...
The Check Engine Light comes back on after I reset it
When the Check Engine Light comes on without any specific warning, this can indicate a variety of possible issues. Unfortunately, without more specific symptoms, this can be tough to diagnose without the use of a scanning tool and the skill...
Getting code p2111 and p2103
Hi there: If you had the throttle body replaced and the error codes still exist, it's possible that one of two things have occurred. First, if the codes were never reset and removed from the ECU, they will still show...
my thermostat housing is leaking
Hi there: Most of the time when the thermostat housing is leaking it's caused by dirt or debris that may not have been fully cleaned out when it was replaced. This will cause the gasket to not seal correctly. Other...
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...
Hummer Certified Pre-Owned (CPO) Car Program
If If you are in the market for a used Hummer vehicle, you may want to check out cars under their certified pre-owned program. Many manufacturers have a certified pre-owned (CPO) program, and each one is set up differently. Read...
How to Gap a Spark Plug
The The spark plug (https://www.yourmechanic.com/article/what-does-a-spark-plug-do) is used to ignite the air/fuel mixture inside the engine. The spark plug (https://www.yourmechanic.com/article/how-to-buy-good-quality-spark-plugs) must be in good condition and must be properly gapped for proper engine performance. spark plug...
Browse other content
Maintenance
Cities
Estimates