Please if there is anyone who can help me. I have a 2005 Prius with 135K miles on it. and last time I change my PCV was 55K. today, my car is misfiring in cylinder. My mon has a Nissa Altima and did not change PCV since day one and one of the Cylinder was misfiring one year ago. My brother change the PCV valve for the Nissan and reset the ECU and no more misfiring. I am wondering if I should also change the PCV valve for the Prius to fix the misfiring issue. and If anyone can please tell me why is a bad PCV valve cause misfiring. thanks
It would not hurt for you to change the PCV valve since it has 80K miles on it. However I doubt that is the cause of the engine misfire. Did you have the iridium spark plugs changed at 120K miles? If not, they should be replaced now as worn spark plugs is a likely cause of engine misfire. If the spark plugs had been changed recently, then check the spark igniter wiring harness connectors to make sure they are securely attached to the spark igniters. The fuel injectors and their wiring harness connectors are also suspect.
Are engine misfires supposed to happen on the Prius? My car has pretty much done some type of engine misfires since we got the car at 61,600 miles. The engine runs rough when the ICE is on and runs very rough sometimes shutting off the ICE. Other times it is completely or relatively seamless. Will the Check Engine light come on when the engines misfire? I have noticed that even with the MAF and throttle body clean, the engine in my Prius still runs rough sometimes. I was told that the car running rough is completely normal by the Toyota dealership. I notice when the ICE is running, the engine runs rougher generally than when only the electric only is on. It does more bucking/jolting when going from drive to park and vice versa, and I have noticed very abnormal unstoppable shaking two separate times when the car was in park.
my mom Nissan Altima was misfired in random cylinders. and I suspect the same thing is happen in my Prius now. my scanner showed that it was misfiring in cylinder 1. I believe when I reset the ECU and scan it again, it will show misfire in other cylinder. anyway, I am not bothering to try this. I just replace the PCV valve and maybe the valve cover gasket since it is already more than 130K and small oil was leak (most likely due to not working PCV building up too much pressure in it) my spark plug was changed when it was at 100K.
1. The Prius has a four-cylinder gasoline engine and by its nature, is not particularly smooth-running compared to an inline six cylinder engine or a V-8 engine. Not only is an inline four cylinder engine not inherently balanced, but it only produces two power pulses for every 360 degrees of crankshaft rotation. Depending upon what you were used to driving in the past, you might think the engine runs a bit rough. 2. The check engine light will come on if engine misfire exceeds a certain % threshold which is relatively high. I think an individual cylinder has to misfire more than ~20% before a DTC will be triggered (which will turn on the CEL.) 3. Electric power alone will be quite smooth. It is to be expected that when the gasoline engine is running, more vibration and noise will be produced. The question of what vibration and noise is normal is somewhat subjective. You may need to drive another Prius for comparison purposes. 4. The issue of abnormal unstoppable shaking is unusual for 2G Prius. Neither my 2004 or 2007 had that particular problem, but I noticed it a few times with my 2001. It was just like a manual transmission car in first gear, if you approach a stop without pressing the clutch pedal. The engine will balk and jerk because it cannot spin smoothly at a very low RPM. If your car is producing that driveability issue, you might look into the possibility of having the hybrid vehicle ECU reflashed with the latest available firmware for your model year.
found the issue, one of the cylinder where the spark plug located has water causing misfire. don't know how water got into it. All I know is it was raining like crazy 2 days ago. and that never happen before to my car. I wonder how those water got into it.
One possibility is that the center seam between the two pieces of plastic cowl covers that's leaking.
As I recall there was a Technical Service Bulletin for a leaky hood. If it has not been performed on yours a dealer will fix the gasket for free.
Usually because it rained so hard it overflowed the water seal on the water dam under the windshield and then it drips on the top of the engine and gets in the ignitors and rusts ignitor connections. Evidenced by alot of rust in the spark well. Usually requires a new ignitor to fix. Btw, there's also a Gen 1 TSB for this includes new seal. If me I would check to see how the water dam evacuates also. Pour controlled water in the dam till it fills up but don't let run over. You should see a strong stream of water coming out for behind both front wheels. If not the dam vents are clogged with leaf debris. Pretty common. Always keep all debris out of that dam area.
Well, the cylinder head is a poor design and it bit you, but it's time to change the title of the thread because as you admitted, the PVC valve had nothing to do with a toyota misfiring, and as is it's misleading, jmho
yes, PCV is not cause of issue for my scenario. but I am going to change the PCV anyway. It is about 80k since I changed it last time. will check the spark plug tomorrow as well and replace the valve cover gasket. It is leaking small amount of oil. I guess due to bad PCV. by the way but I change the valve cover gasket anyway on a 135K car. I found that bad PCV can cause misfiring due to incorrect air/gas mixtures. google it and you will find it. I think I just keep this title so that other prius can aware of this.
