nate V

Big surprise huh. I have 95' 4rummer California emissions 3.0 engine that just wont run correctly. Symptoms- Starts rough like it is missing a cylinder usually, when it is idling correctly after it has been warmed up for a bit it typically comes right out of it but when I begin driving when the engine is under load it immediately bogs way down a loses one or more cylinder, this same thing happens when I change gears from 1st to 2nd . I can rev the engine a bit and it typically cones right out of it. After I move past this rough take off stage it runs like a champ and there is nothing wrong. I am in desperate need of help any suggestion would be much appreciated.

terryjmatthew

Have you checked the most common causes?
Cap, rotor, plugs, etc.

nate V

I have, Cap rotor plugs wires, checked the timing was at 15 and retarded it to 10 like suggested and no change, i have instaled 2 new o2 and a throdle positioning sensor as well ..no change I have doubts about the vacuume system on the throdle body i have one line pluged off and do not know where it goes???

gilby4runner

post a pic of the line in question and see if anyone can give you more info.

MonsterMaxx

has it had the headgaskets done?

my 91 did what you describe, what had happened is that the HG let go (like the 3rd time) moisture had rusted the cyl walls, eventually pitting them, very low compression on one cyl.

It hardly smoked at all, just the barest amount on startup.

Do a compression test.

nate V

Thanks I will do a compression test on it later today. I do not have a pic of the vacuume line but i will post one after a take a pic of it. yes i do believe the head gasket has been although toyota can't give me a deffinate yes or no on it.

nate V

Is there any chance this could be all caused by the brake booster???? I just read another thread that stated they had serous issues with the engine performance due to a bad brake booster that was possibly leeking?

CyMoN

check you MAF

terryjmatthew

The 3VZ has a VAFM if I am not mistaken. That could be a possible cause.
I would first do a compression test before spending any more money.

nate V

What is a VAFM......? and with regards to the MAF I have replaced the mass air sensor I actually have 2 or them one left over from the engine i had in the truck before neither of them seem to make a difference when instaled, i know it is not jamed up because when i rev it up i can hear the door slam shut....

What is this seafoam i read about erlier in another thread? It helps clean out your vacume system...?

rdharper

The 3VZE does not use a Mass Air flow meter... it uses a VAFM.. volume air flow meter. Totally different method of doing the same thing. This is an air gate system tied to swing arm which measures resistance proportional to the angle of the air gate. It is the voltage across the variable resistance which is fed to the ECU.

tc

Bad brake booster would esentially be a bad vacuum leak.

x3 for the compression and leak down test, then go from there...

If compression is OK, I would look at the ignitor/coil pack - they have been known to go bad over time. I had strange vapor-lock type symptoms with mine, and it turned out to be the ignitor/coil pack.

nate V

I did not know about the air intake sensor being a set up the way it is. thanks for the info. I will do the compression test when I get home. Is it possible for the igniter to go bad and not the coil itself???
I have had the vacuume system checked and it seemed to be with in limits so maby it is not a bad booster afterall.

rdharper

If it is the VAFM, the failure mechanism is on the resistance phenolic that the pickup swings across. It wears a track in the phenolic so resistance is unpredictable. If that is the problem, it will steadily get worse such that you can't even get the vehicle across the street. The problem usually shows up at idle, but is inconsistant as it feeds the wrong info to the ECM, as the wear increases in the pickup track.

As to where it is, it is the square box, a couple of inches square, black in color, just after the air intake, over the air gate.

It could explain the problem, but if you've replaced it, less likely. They all fail the same way, but are usually good for 200k miles or so.

tc

I guess, but they are all mounted together, so you will be replacing both.

nate V

No time for a compression test tonight although i am not losing any coolent or oil so i do not think that it is leeking. The coil on the other hand did not check out ok. I did the resistance test sugested in the book and found the
2nd coil to be with in limits but the primary read .006 when it was supposed to read somewhere arround .035 ....and ths insulation reeding was non existant or maby it was just infinate...makes me wonder if i have a bad coil?

nate V

the line that is pluged off on the throdle body is the one im not so sure about i believe that it has something to do with the California model.....I dont know where it goes to or what it controls, ........??? any ideas

SEAIRESCUE

Looks like a factory plug. You can put a vacuum gage on it so see what it reads at idle and when you crack the throttle. You can look on the back of the engine to see if any of those vacuum devices are missing a hose. If not, I suspect it was built that way.

nate V

i wish it were that simple but i put the plug on it when i put the engine in. I have looked for the other end and cont seem to see where it goes....so i dunno but i like the idea about uptting a gage on it. thanks

93caddyrunner

did u check your coil