Q: Car is showing random misfire code po300

asked by on June 13, 2016

I accidentally let go of clutch and gas in 1st gear causing car to turn off and jump foward, after i turned car back on it started shaking extremely bad, check engine light came on and now idles rough at 100 rpms normally would be at 1000 rpms. While driving it home like that i noticed that normally i would change gears at 3500 to 4000 rpms instead it was needing to change at 2000 rpms no matter what gear i was in. Ive changed the spark plugs, spark wires, coil pack but i dont want to keep wasting money on random stuff im hoping someone has had this happen to them i need help please

My car has 123000 miles.
My car has a manual transmission. Here is video link of my car.
https://m.youtube.com/watch?v=BrA6CY3R6uU&feature=em-upload_owner

Car idle is rough Inspection $94.99 - $114.99 Get a Quote

The only sensor that will cause the RPM gauge to read incorrectly and cause a rough running engine is the crankshaft position sensor, or its wiring and connector. Try and disconnect the crankshaft sensor connector located above the oil filter on the side of the engine block. Look for any damage to the sensor or the connection. If you do not see any damage then the sensor should be tested or replaced and the codes cleared to see if it corrects the problem for you.

If you need assistance, a certified mobile mechanic can come to your home or office to inspect your vehicle’s issues and provide any 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


Experienced Mechanic?

Earn up to $70/hr

What others are asking

How do you use the automatic heater and air conditioner?
If your car is equipped with an automatic climate control system, using it is actually very simple. Here’s what you need to know. For the heater and air conditioner to work in auto mode, you need to first press the...
Shifter will not go into gear
Hi there. This can be an issue with your shift linkage being loose or not correctly adjusted. It also can be something malfunctioning inside of your transmission. I suggest having a certified mechanic, such as one from YourMechanic, take a...
Faulty water pump causing car to overheat
If coolant is not circulating, even with the thermostat removed, the problem may be with the water pump. It could also be a clogged radiator, but is not likely. If the coolant is circulating, the problem could be with the...
Windshield wiper clicks and engine revving heard on radio
Yes, corrosion on a ground terminal or splice point can cause various engine and electrical systems issues. Looking at the wiring diagrams I see nothing related between the entertainment and engine control systems that jump out at me as the...
Car hit by lightning and won't start.
You will need to have the vehicle towed to a dealer. I have seen many vehicles like this and in most cases, if not all, the computers in the vehicle get zapped and fried. I would recommend contacting your insurance...
Car starts then 3 seconds later it dies
Hi there, thanks for writing in. There may be a problem where the ignition relay is losing connection and causes the vehicle to stall or not start. You might need to replace the ignition relay (https://www.yourmechanic.com/services/ignition-relay-replacement). If you would like...
Driver side power seat seams to only want to move back on one side creating a pivoting motion
This issue is common enough that YourMechanic (https://www.yourmechanic.com) has devoted a diagnostic and service page to this problem of faults in power seats (https://www.yourmechanic.com/services/power-seat-is-not-working-inspection). Indeed, if you simply request a power seat diagnostic (https://www.yourmechanic.com/services/power-seat-is-not-working-inspection) the responding certified mechanic will promptly...
Nothing happens when I push the gas pedal
The P0104 is probably the key. This is a code for the Mass Air Flow circuit. What it means is that the reading from the MAF is not along the lines of what the ECU expects. The 171 and 174...
FNR5 Transmission skipping 2nd and 3rd gears.
It is very possible that there could be pieces of RTV in the valve body causing a restriction. It is also possible that the transmission itself could have some internal damage causing this issue. I would recommend having the vehicle...

Related articles

A Buyer’s Guide to the 2012 Mitsubishi Lancer
If If you’re looking for a compact that delivers a sporty driving experience, the 2012 Mitsubishi Lancer just might be the right car for you. With a variety of models to choose from, including both a hatchback and high-performance option,...
A Buyer’s Guide to the 2012 Mitsubishi Galant
If If you’re in the market for a midsize sedan and want the best price possible, you may be thinking about visiting a Honda or Toyota dealership. Before you do, check out the 2012 Mitsubishi Galant. Key Features Considering how...
Mitsubishi Certified Pre-Owned (CPO) Car Program
If If you have been shopping for a used Mitsubishi 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 on...