hard to start, a leaked injector?

Corolla 2000 with 200k km

To deal with a code 0300, 4 spark plugs and 4 coils were replaced originally. But right after I replaced the 4 fuel injectors, a new problem arose and it would crank for 2 or 3 seconds when starting, however there's no problem when I restart within a couple of minutes. Now it occasionally reads check engine code 172 and 300. The problem persists after replacing fuel pressure regulator and MAF sensor. Is it possibly a leaked injector? (the battery is okay)

OBD data (idle)
Long term trim -28.9
Short term trim -10.4
MAF 3.43
ETC 75
IAT(C) 31

Any input would be appreciated!

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Mostly guessing here but your 172

seems to indicate a mixture that's too rich. This makes sense if you're engine is misfiring. Do you notice any random misfires? I'd also ask if the parts you used were OEM or after market. From what I understand, Toyotas and some other Japanese cars are finicky about parts. In the Toyotas we've had, I tended to use only OEM parts in certain applications. I bought Denso plugs and wiring as well as any part that generated a code related to a sensor. FWIW, and when I did spark plugs, I also used dialectic grease during assembly. The jury may still be out on this practice but I've always followed it as it does help get things back apart as well as help prevent corrosion that leads to arcing.

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Steven; You are absolutely right in suggesting dialectic. We also use anti-seize on the spark plug threads on aluminum heads.

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You're probably more experienced than I

as I don't do this professionally. I do know that the last plugs I replaced came with a coating so no anti-seize was to be used. If using that stuff, however, one should consider that adjustments to the torque specs may be needed because the lubricant fools the tools. I've made my share of mistakes but I do recall an old saying that goes something like..."When all else has failed, read the instructions." Happy

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Injectors are after market ones.

I will order some Denso and update afterwards.

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Before using a "shotgun" approach

I'd do my best to verify that the fault codes were valid. Misfiring and rich fuel should have obvious symptoms. You'd hear or feel the engine misfire and fuel too rich should be detectable at the exhaust. Sooty deposits or the smell of unburned fuel is easy to verify so I'd make sure to check this before tossing parts into the car. Often enough, a person can introduce a problem that wasn't there before.

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Denso is one of the best plug out there

I'm a denso guy as well. Works better than other brands I've used.

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problem fixed

1) problem of hard to start fixed by replacing with Denso injectors
2) rich trim 172 disappeared after switching back to previous MAF sensor (cleaned with tissue paper)
3) painful lesson learned to avoid after market parts
4) A BIG THANK YOU to MR Steven Haninger !!!

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Glad to hear but sorry to be late

I hate dealing with ambiguous engine codes. On older cars, they'll often lead you on a wild goose chase. As for OEM parts, I'm hearing that some ECMs may be able to detect aftermarket parts and deliberately misbehave because of them.

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