Fuel injector electrical connections (misfires in 1, 2 & 3)
 

I've had a problem with cylinders 1, 2 & 3 misfiring but it's still going on after some fixes. I already replaced the secondary air pump (it sounded horrible so it was time) and replaced all three coils on that side and the plugs. I plan to replace the coils on the other side since I'm at 200k miles, but could only find 3 to buy at the time. I'm still getting misfires on that side so I'm guessing it might be the electrical connection to the fuel injectors. I don't think all 3 injectors would die at once. Anyone know where the fuel injector electrical connections are and if there is a connector for each side and if theyre easy to get to? I had a mechanic fix some vacuum leaks and that's when this started happening so I really think something is just loose.

Thanks for the help!

Do you have a MIL code & if so, what is it ?
If you have no code, it could be more vacuum leaks.

I had a connector related misfire, but only at one cylinder. Just needed to be snapped more solidly in place. They connect to each fuel injector - just follow the wire. Pretty easy to spot.

If you let a mechanic work on it, I would check that your coils are fully connected. The rubber covers secure the connector good and it's easy not to fully push the connector to lock.
I would do the same thing with the fuel injector plugs. If it doesn't fix your problems it's easy to mix up vacuum hoses. That was my issue.

300,301 & 302 are the codes. Misfires in all three right-hand cylinders.

I did the coils/plugs myself after the problem started so I know those are tight and they're the new, updated type with the longer screws. Where can I find the fuel injector plugs? I'm thinking they unclipped the plugs when they were fixing vacuum leaks and they weren't secured properly when they finished since it ran fine for a couple of days and then all of this suddenly started happening.

Check common connections first, like your engine ground strap. A bad connection could lead to an excessive voltage drop.

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A high resistance ground strap would cause all sorts of other problems too - including the other 3 (good) cylinders to misfire.

since entire bank is in fault then misfires could also be due to timing on that bank, or faulty o2 sensor setting bad trim. with a durametric you could record actual values for fra and cam position.