Need help with '91 4runner

'91 4Runner, V6, 3.0, 113K miles. It has a nasty bog on takeoff, doesn't seem to clear out until over 35 mph on flat ground, and you can forget about starting from a dead stop going up any sort of incline. This is not my vehicle, it is a relatives, I drove it for the first time today, and thought that I might be able to help.

It still has the stock plugs, so I figured those were up for changing anyway. While I was at the shop, I went ahead and picked up a new air and fuel filter. I decided to try one thing at a time, started with plugs, got em in fine, took it around the block, wouldn't idle, sputtered pretty bad, stalled at every stop sign.

I figured that the fuel filter was in fact clogged, and maybe the new plugs were causing it to starve for gas? Crawled under the car, and the cat converter was cherry red hot. I put in maybe half a mile, so could that be my problem? It has begun to rain, so I have not installed the fuel filter, and thought I should get some opinions. I've heard some stuff about sensors going bad, namely the CTS, but that is getting a bit in over my head.

I greatly appreciate any advice.

Short terminals TE1 and E1 of the ECM connector under the hood. See if you get codes from the Check Engine Light blinking. Normally, you will get regular blinking about 4 times a second. If the blinking is irregular, count the blinks between pauses. They are numerical codes indicating a source of trouble.

Is there a smell of gas under the hood? Check the fuel pressure and volume at the fuel rail.

Just replaced the fuel filter, and it feels like it has less of a bog, but it still barely maintains an idle at 300-400 rpms. I noticed an odd ticking noise under the hood, in the dark I realized one spark plug boot is lighting up, I must have missed this in the daylight. I will be replacing the wires (Hopefully this might clear up the issue of the low idle), and then I will get to seeing if there is any error codes. How would I go about testing fuel pressure? If it is the fuel pump, I probably won't get into that myself anyway.

To test the fuel pressure, you would buy a pressure meter and necessary adapters to tee off the fuel line. I doubt you'll need to. I think the wires will solve your problem. Check the codes anyway. You may be surprised. I mentioned the smell of gas because that engine is known to leak from the fuel line pulse damper, near the firewall.

Just replaced the wires and it seems to have really cleared up the issue. Seeing as its not my truck, I'm just gonna leave it at that and not bother with the error codes. Also, there is no smell of fuel, and I don't notice any fuel/ gunk buildup near the firewall. Thanks for the help.