ok everybody this is my first post so bear with me... i own a 91 4runner v6 3.0L EFI 4x4, i have recently replaced the clutch, 8 month old rebuilt transmission, spark plugs, plug wires, dist. cap, rotor, took off the cat converter, flow master muffler, changed brake master cylinder, clutch slave, airflow sensor, cleaned out the ERF, new fluids, and the car still hiccups when I'm on the freeway or sometimes when I'm just about to shift to second gear. when that happens the check engine light flashes just as quickly as the car hiccups.... it almost sounds like the motor shut off and turns right back on.... the radio and lights never go off, it just sounds like the motor....
i have been reading and some say it could possibly be the o2 sensor or the throttle positions sensor, but i just want to get some confirmation from everyone before i go ahead and buy parts that are not necessary as of right now.... if you have any ideas or information please let me know

 

i also forgot to mention that i have been using a fuel additive which takes the water out of the fuel, lowers the ignition temp, cleans the engine gunk, and helps with emissions.... the product is called xft.... if you interested here is the link...
xfthonolulu.goxft.com

 

1. Don't just start throwing parts at it.
2. Use the link in my signature to get to the FSM online, see how to check your computer codes using a jumper and flash out. "MFI System Diagnosis"
3. Break out your multimeter and test parts that may have issues, once again, using the FSM for diagnostics.
4. Stop using XFT. Add something proven to clean out your system, such as STP water remover if you have water in the fuel, or even better, put 1 ounce of SeaFoam per 1 gallon of gas in your tank, and this will clean out everything in the fuel injection area. Use the other half to clean your throttle body by dumping it into your throttle body using vacuum or brake line (many writeups on this site about this). READ Instructions for this!
5. Fuel Filter

 

So I ran the diagnostic test and its not giving a code, just flashing on and off which means that it is at normal operation....

 

Step 3: Follow the FSM MFI System Diagnosis using the manual and your multimeter.

 

I'm going to throw out an issue with the igniter, maybe a loose ground or some other intermittent connection. the codes associated with it aren't "sticky" so they won't be there if the CEL isn't on when you check.

check the plugs to/from the igniter for any corrosion and check that the terminals are firmly locked into the plugs.

and make sure the coil and all the plug wires are at least 1" away from any metal so they don't short out on anything

 

ok so today i ran diagnostics straight from the ecm using a multimeter to test voltage.... all read pretty well when i tested vs-e2 idling the car would bogg down and as soon as i removed the tester it idle picked up again.... (vs) is the volume air flow meter.... i have to admit that when the hood is open and the truck is running , if i touch the afm anywhere i get shocked.... its weird cause i just bought a brand new afm not more that a month ago...

also, when i tested igt-e1 idling the car would just die out.... I'm wondering if these have a connection and a reason for the power loss and bucking.... the igniter looks as if it is the original one.... and i am wondering if that is the reason why the afm is hot... not sure... I'm stumped... all the grounds are good, i tested the o2 sensor and that is good.... i listen for the fuel injection, and it seems to be ok.... but i didn't open it up and take a look....

 

Open the FSM "complete wiring and electrical manual" and open the "E.W.D. 1990-1995::1995 4runner: Engine Control (3VZ-E) " section. Test the wiring from the ECM to the AFM and from the ECM to the coil / ignighter. Check for continuity on each wire. You probably have a shorting wire in these looms. Possibly a bad ground. Remove the ignighter pack, and use a steel wire brush to clean off the contact areas for better grounding there. Do you have the ground wiring that comes out of the main loom, drivers side, near the ignighter that goes to the drivers side head? Do you have a resistor box with a C prong that is bolted down underneath the ignighter? What kind of a shock? Light electricity or a huge Jolt? Still wondering where you are located?

 

its a light quick jolt but enough to make you move your hand away as soon as you feel it.... and i am from kapolei oahu

 

And there is a ground wire going from the drivers side head (it's a little dirty and greasy . I'll clean it up as soon as i get home) and it runs to the driver side fender.... Not right next to the igniter but further down.... I'll take a pic when I get home... Is that where it should be? In that general area?

 

You may want to take a look at your new AFM. A short in the wiring shouldnt' cause you to to get shocked at the AFM.
My guess would be it and not the wiring.
Especially if it's a parts store special.

 

It used to do the same thing with the old afm so I don't think it's the afm itself...

 

Gotcha.

Will the AFM shock you with the key on and engine off?
Voltage at those wires shouldn't change either way.

In fact most of your engine wiring has the same current flowing through it either way.
Just the Alt charge wiring, coil/dist wires and fuel pump wiring shouldn't.

So, if it won't shock you, you may be able to narrow that down.

Also, look around the AFM and make sure no wiring is touching it.
Disconnect the AFM connector and check it out.

 

ok so the afm wasn't shocking me when the key is on and the engine is off.... but as soon as i turn the engine on the thing jolts the crap out of me... lol.... anyways.... I'm not sure if there is supposed to be a ground wire coming somewhere from the afm, but i rigged one..... i ran it straight from the afm to the body and it no longer shocks me when the motor is running.... yay ! and so far the hiccup hasn't come back (hopefully never does) but i haven't reallllllllly tested it out... i just drove it around the neighborhood.... but before i put the ground wire on it would hiccup at least 3 times before i even got to the top of my street...(mostly cause the engine was cold i guess cause it would happen less frequently after warming up) i hope this helps with the power as well.....

 

If you would look at the FSM, Electrical, E.W.D. 1990-1995::1995 4runner: Engine Control (3VZ-E) , you would see that the solid brown wire is the ground. You may want to check the wiring from the AFM connector (brown wire) and see if it is shorting out with a powered wire somewhere before you have an electrical fire!

 

thanks for the advice... now you got me worried... lol.... well the wires at the connection don't look burnt or anything... and the wires are all in the wire sleeve so does that mean id have to that the whole wiring system out to follow the ground to see if there is any damage... as far as i can follow it everything seems to be in good shape... but i could be wrong....

 

Use a multimeter and attach one lead to the brown wire at the AFS, and the other lead to the actual ground point under the drivers side left kick panel (IE in the image) test for continuity, repair or replace the wire correctly as needed.

 

i checked from the brown wire to the ground and there is continuity..... I'm stumped!!!!

 

Make sure you isolate any wires or components you are testing for continuity. Wouldn't want any other circuits to provide a different path and give you a false reading.

 

When you tested, did you remove the jump ground wire you installed? If so, then you are going to need to follow the wiring schematics in the FSM, and test continuity on all the wiring for the AFM from the connector to the different areas they go (ECM, other components) until you find the problem. I can not guide you one wire at a time.
Do you have a copy of the FSM yet? There is an electrical section and a repair section. Look into the electrical section, print out the wiring for the 3VZE, and test.