Hey all, my wife’s 2009 Corolla has been taking a few turns to start. There’s misfires in every cylinder, and the engine shudders.
It was running fine when we got it around a year ago, and the problem slowly came about. I’ve replaced every ignition coil and spark plug, and they’re all firing fine. Then I thought it was oil getting into the spark plug wells, so I attached a straw to a shop vac and stuck it in each one (not much came out), then replaced the valve cover gasket.
It seems to be a fuel issue, but my fuel pump seems fine. I was thinking maybe it’s sensors, but I’m really lost and I have got to keep this vehicle running! Any advice would be welcome.
If not fuel, not electric, then maybe air? Check the air intake hose (that big one between air filter and throttle body) to see if there’s any leak(as in any dry rotten crack), especially if there’s an airflow sensor right before the hose, it will cause misfiring because of the inaccurate airflow reading. Then check all the vacuum hose to see if there’s any leak.
If it’s sensor, it usually will throw a code(and the “check engine” icon will light up) and you can read it using a scanner.
Got it. Thank you!
Check the fuel filter. Maybe you got some bad gas, or you let your dog shit in the neighbor’s yard and he put dirt in your gas tank to retaliate.
Pull all codes, (all of them), lookup EACH one.
One will be the root cause.
There’s a $5 code reader that works over Bluetooth with the free app Torque. I’ve used it for years. Do NOT leave it connected to the OBDII on a Toyota - it’ll cause spurious codes. Throw it in the glove box when not pulling codes.
https://www.amazon.com/NYTKL-ELM327-OBDII-Diagnostic-Scanner/dp/B0F62RX7YV
Toyota’s are staggeringly reliable, especially a 2009 Corolla - it’s the same engine they’ve used forever, but updated with a modern ignition system. It probably didn’t need coils or plugs (plugs maybe). When a coil is bad you’ll get a code for that specific coil.
I’d be more inclined toward a vacuum leak in the intake downstream from the MAF sensor. Check the hose, see if there’s a crack. A simple trick is to start the engine and spray anything along the intake hose - WD40, carb cleaner, brake clean, etc. If it sucks it in the engine will stumble and you’ve found the vacuum leak.
These are very simple engine setups, little to go sideways. And codes are pretty accurate on these engines.
Have you checked codes to see if there’s a clue there?
Codes run misfires and a bunch of random shit. I don’t have a code reader myself, but I can borrow one. My mechanic fixed a wiring issue recently that I thought caused the issue, but I guess not.
If you can pop into an Autozone or place like that they can read codes on all modules; just don’t listen to their diagnosis. When you get the list of codes, DM them to me and I can see if I can find some common fixes on them
Thank you. It may be tomorrow before I can get up there but I will.
Any ideas on what the wiring issue was? Could be a clue as to what is going on now. Especially if it started after the last issue was fixed. Could be as simple as something left unplugged. I have done that more than a couple times working on my own vehicles.
It started before that, but one day wouldn’t start. Fixing the wiring helped get it started again, but it still rattles.
Is the check engine light on while driving? If so, does it stay on solid or start flashing after a bit?
Yes, and it’s solid.
In a way that’s good. If it starts flashing while driving, that means you are probably destroying some expensive catalytic converters.
But that being said, if the light is on, a list of active codes will help us help you tremendously. Most all major parts stores will check your codes and give you a printout to take to your mechanic for free.
Did you check the fuel injectors by any chance? Misfires could be the source of the engine shudder for sure.
I’ll add that to the list of stuff to check.
