Low/Rough Idle after oil change.
 

Specs: '97 4runner SR5, 3.4 v6, 134,000 miles, 4X4

I just changed the oil on my truck today, and when I started it up (immediately after the change), the oil light went on for about a half-second, and then turned off, which seemed normal to me at the time. I let it idle in park for a minute or so while I cleaned up all of the split oil. I then poped it in reverse and noticed the RPMs went down to about 550 and the engine started shaking and ticking, like it was gonna stall. I backed out (giving it some gas), and parked and immediately turned off the engine. I've been afraid to touch it since.

I suspect that in park/neutral the RPMs are about 750, and in drive or reverse they drop to 550, I've double checked the oil level, the cap, filter, and plug, and everything seems to be in order. There are no loose hoses, or anything that may have caused a vacuum leak.

I need to drive about 300 miles tomorrow for an interview, so it would be nice to get this fixed tonight, and any and all advise is appreciated.

That's a strange one. Wrong weight oil? Filter not on tight? You're sure you drained the oil and not the diff or the tranny right? How full is it on the dipstick?

I put in 5w-30 castrol gtx (same as I had in there), right up to the full mark, with a Toyota filter, and everything is nice and tight.

Just went for a test drive. Things seem to be back to normal. phew.

Still kinda curious why this happened though.

Gremlins.

So today I'm driving to the store, everything seems fine, and then the CEL turns on and it starts running rough again. I think i'm running on 5 or 6 cylinders depending on my truck's mood.

I tried to get a code by jumping the diagnostics port, but the airbag, cruise, and abs lights just started flashing at different frequencies. What am I doing wrong?

Get the codes read at an Autozone, O'reilly's, etc.. for free or buy a scan tool for the future. Then let us know what it says and we can go from there.

The autozone guys are great with this.

As long as you have an OBDII car, otherwise, no.

Silly question but did you double check the oil fill cap is on? Because the rough idle sounds like a vacuum leak...

So I went into the mechanic... They read the code. I have a mis-fire on the #3 Cylinder, and they determined that the injector is kaput, and they wanted $600 to fix it, so I promptly left.

So, I guess my question is, how hard is it to replace an injector, and how much would a new injector run, price wise?

Hole 3 is a straight shot (you don't need to pull the intake plenum off) so $600 is insane. I've done an injector on theat side in a 1/2 hour. The injector was ~$80 for a rebuilt one I found at O'Reilly's. I'm sure a new OEM injector would be more, but I can't see it costing more than $200 total at a shop. It's not hard to DIY, but buy the upper and lower 0-rings for the other 2 on that side (I think the set was ~$5) because once you pull the fuel rail, you should replace all the o-rings to prevent it from leaking.

ok this might be close to what im having go wrong right now... my truck idled really low and rough like a miss fire then i let it idle for a while and it got really rough and then back fired really loud then ran fine but when i would go to drive it and get around 3000 rpm it would retard out and pop and everything.. could i do a top engine cleaner run the can through the injectors maybe its clogged?

Yours sounds like an ignition timing problem to me.

If he only needs one injector is it worth it to just swap that one out or send then in to be cleaned and tuned <=(couldn't think of the right word)?

So I bought an injector ($116), and replaced it, I did the valve cover gaskets, and spark plugs while I was in there, and everything seems to be running well now. So it looks like it was just a coincidence that the injector failed immediately after I changed the oil.

Anyway check out what the plug in cylinder 3 looked like. (3rd from the left)

Attachment 186869