Alright, so I have a v6 EFI 4wd pickup and it's been acting up lately. Just the other day I would be driving then it would hesitate and the RPM would drop 500 and start backfiring for a few seconds and start running again. I thought it was some water in the tank but after I put some Heet into the tank it started running worse. Now it would just lose power shut off out of nowhere. The only way I was able to get it home was to press the clutch cancel, hold the gas to the floor, put it in first, and hold the key on Start for about 20 seconds until
I can get enough speed then pray it won't stall out again. I recently had the fuel pump and filters replaced so I don't think it could be that. I'm at a loss of what to do because I can't really afford high mechanic bills right now but at the same time I use my truck to work, so every day my truck is off the road I don't work...HELP?????

 

Check engine light coming on?
Have you pulled trouble codes?

 

Well the light has been on for over a year (that's when I got it) and I haven't had many troubles with it until recently. I just pulled the numbers and I got 4-2-5-2 but why would it say Airflow Meter twice?

 

Air Flow meter? Air Flow meter code(s) are 31 and 32.
Which codes did you get exactly? because out of those numbers you could have gotten: 22, 24, 25, 42, 52. I'm guessing you got 42 and 52. 52 is Knock Sensor Signal, and that could cause your problem if its retarding the timing a lot.

 

Well, this was my first time pulling codes and I just followed this website
http://www.troublecodes.net/Toyota/

 

Gotcha. Codes 1-12 were for earlier model 22res. All the 3vze codes start at 12.

 

So where would the Knock Sensor be in this rig? I've looked for over an hour

 

sorry to say the knock sensor is located in between the two heads and threads into the block. I would make dang sure first that it was this before taking the intake plenum, intake manifold and all the hoses that go with it off..

 

ok i've had a few 3.0s with knock sensor issues.... #1 it will not cause the truck to do what your talking about i'm sure.... if the engines running bad enough and missing firing enough the knock sensor will catch this and throw a code.... if the sensors faulty ok it will not cause much of a prob. the engine reacts to it alittle bit but not like your talking about. i forget what code 42 is but thats mostly where your problem lies. whens the last tune-up its had? timing correct? fuel filter on backwards? Mass airflow? I know this sounds odd but try beating on the mass air flow box when its running bad.... if it helps the truck it may be where your prob lies. vaccum leaks? have you tried reseting the computer to see if anything changes in driving? Pull EFI fuse out for 30 secs and and out back in and see.... intake manifold leak?

 

42: Vehicle Speed Sensor Signal

 

EGR fault? Mine had an idle that sounded like a cammed-out v8 when the EGR vacuum on top went haywire...

Backfiring can also be caused by a bad distributor.

 

I've had symptoms like you describe. Got steadily worse over a few weeks.

I traced it to the AFM. There is a phenolic layer which has a swing arm on it, which tells the ECU the angle of the air gate.

The phenolic was scored due to long use.... this was on the '85, not the '94. About 200k miles.

Tried fixing it with conductive epoxy... worked for awhile. Ended up replacing the unit, which fixed the problem.