So I've acquired a relatively clean, rust free and low mileage 95 4 Runner (3.0 auto) for next to nothing. Don't know too much history on it, I'm the third owner. It starts and idles just fine, doesn't make any weird noises or indicate anything wrong. However, once put in reverse or drive, it wants to bog down and stall, regardless of temperature. It does seem to resist stalling slightly longer once warmed up, but still isn't driveable. From what I was told, and what I can see, a lot of parts were replaced under the hood, but they weren't able to pinpoint the issue. Most of the vacuum lines are new and the rest appear to be solid. I pulled the codes and found 14, 24, and 31. Appears to have a newer AFM, but from what I can see, all the ignition and vac switches are original. Luckily, I have an identical 95 that had a bad trans, so I can rob some engine parts if needed. Any suggestions on where to start? More of a Jeep and VW guy, so this thing is slightly unfamiliar to me. Thanks in advance for any advice.

 

If your going to be wrenching on your 4R yourself get a good FSM.
with the codes your showing, the first thing I would do is to check all ground wire connections for any corrosion and then use a vacuum diagram to check
that all vacuum line are where they should be. Just one of them misplaced can cause mayhem on these motors. Good luck.

 

It's going to be just me wrenching, since one could go broke paying someone else to maintain it. I wondered about the vacuum lines, since there's a ton of them. Guess that will be fun to sort through. Any particular grounds that are known problems? Didn't see any that looked bad, but that doesn't mean I didn't overlook one either. Thanks for the tips, gives me a good starting point to work from.

 

On yours, should be fender to ground on battery, engine to firewall, frame to body.
I also make sure my coil/igniter mounting bolts and connection is corrosion free.

 

Always a good sign ....

As KSTI said, you do need the manual.

24 and 31 are both related to the VAF; if the it is disconnected (for instance). So test it: http://web.archive.org/web/201003261...92volumeai.pdf

(Just to save you some heartache: NEVER remove the screws on the VAF connector. Just ease up the clips on each side (like the CSI connector), and pull the connector free.

 

And it's completely possible that the last guy DID remove those screws on the VAF connector, and in so doing trashed it. If that is what happened, you can usually repair it if you're good at precision electronic soldering, but it might be easier to replace the VAFM with one from your parts truck.