Just did a tune up on my 1993 4Runner 3.0 and immediately after I started the vehicle, I noticed that the idle was abit rough. It will idle very low, around 500 rpm until i hit the gas, then it stabilizes around 900 rpm. I was carefull not to throw the gap on the plugs out when installing them so that shouldn't be a factor. Im not to familiar with the Toyota electronics but is it possible that the ECU is just readjusting to its new state of tune as the plugs and distributor cap and rotor were on their last legs. If not i guess i better recheck the gaps.

 

Make a note of everything you worked on and go back over it with a fine tooth comb. I ususally start the truck after everything I work on just to be sure it wasn't that one thing that caused the truck to run poorly (then I have the problem area narrowed down considerably. It could be that the ECU was compensating but I would have thought that it would make the idle rise, not go down. If you need to pull the plugs to check the gap again I would do that and also check the resistance in the plug wires to be sure one was not broken during install.

 

It sounds like a cylinder isn't firing. Pull wires until the idle doesn't change. That's where your problem is. It could be a plug, bad wire, or the distributor cap.

Good Luck

 

Be sure to ground the wire to the block when you do this.