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2009 Corolla 1.8L rough start and shudder (lemmy.blahaj.zone)
submitted 4 months ago by VerilyFemme@lemmy.blahaj.zone to c/mechanicadvice@lemmy.world
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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.

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[-] psx_crab@lemmy.zip 6 points 4 months ago

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.

[-] VerilyFemme@lemmy.blahaj.zone 3 points 4 months ago

Got it. Thank you!

[-] Smeagol666@crazypeople.online 5 points 4 months ago

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.

[-] LecternCistern@sopuli.xyz 4 points 4 months ago

Did you check the fuel injectors by any chance? Misfires could be the source of the engine shudder for sure.

[-] VerilyFemme@lemmy.blahaj.zone 3 points 4 months ago

I'll add that to the list of stuff to check.

[-] cxg@lemmy.world 2 points 4 months ago

Have you checked codes to see if there's a clue there?

[-] VerilyFemme@lemmy.blahaj.zone 4 points 4 months ago

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.

[-] LecternCistern@sopuli.xyz 3 points 4 months ago

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.

[-] VerilyFemme@lemmy.blahaj.zone 1 points 4 months ago

It started before that, but one day wouldn't start. Fixing the wiring helped get it started again, but it still rattles.

[-] cxg@lemmy.world 2 points 4 months ago

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

[-] VerilyFemme@lemmy.blahaj.zone 2 points 4 months ago

Thank you. It may be tomorrow before I can get up there but I will.

[-] seathru@quokk.au 1 points 4 months ago* (last edited 4 months ago)

Is the check engine light on while driving? If so, does it stay on solid or start flashing after a bit?

[-] VerilyFemme@lemmy.blahaj.zone 1 points 4 months ago

Yes, and it's solid.

[-] seathru@quokk.au 1 points 4 months ago

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.

this post was submitted on 16 Jan 2026
11 points (100.0% liked)

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