mathyou

This is my first time posting here, but I have been reading a bunch and really appreciate the knowledge of people on the board. If this is in the wrong area, more info is needed, etc. let me know and I will fix what ever is needed.
My truck is a 2002 Extended Cab Tacoma 4x4 with the 3RZ (2.7L) engine, and manual transmission. The truck has almost 82k miles on it. We bought it used a year+ ago with 67K miles, and has been working great with the exception of this recent issue.

Here are the symptoms I've noticed:

- When climbing hills at highway speed, or accelerating in 4th or 5th gear (3rd sometimes too) we can hear a rhythmic "chugging" noise (my wife described it as a "clicking sound") that we did not used to hear. If we let off the accelerator it goes away (and we slow down), but as soon as I press the accelerator again enough that it’ll hold or increase my speed the noise is back. Driving around town or on a flat freeway where the engine is not under such a heavy load everything sounds normal.

- When climbing hills the engine feels like it loses power. I know this is the 4-banger, but it feels weaker than it used to, and I'll have to down shift for hills I did not used to need to.

- Decreased gas mileage. We used to be able to get 24-25 freeway, now we're getting more like 19 - 20 on level freeways.

- I did a compression test with a kit that was borrowed from Auto Zone. The results were (from front to rear) 100, 100, 90, and 120 psi, which I don’t like, but also don't trust too much as I don’t think the hose that screwed into the spark plug sockets sealed real well. I was hoping this would tell me something more, but at the moment do not trust the results, and would like to repeat it.

- When I had the spark plugs out for the compression test, I checked them out. All were gapped properly, but one of them had a lot of black carbon build up around the base (though none on the electrode).

- Another thing I've noticed, but has been around longer than this issue is when the engine is warmed up, and idling it will unusually idle at ~750rpm, but every now and again will drop down to ~500rpm for a split second before going back to 750. I don’t know if this is related or not, but figured it would be good to put out there.

So my question is does anyone have any ideas what may be going on here?

Thanks in advance. I really appreciate the help.

~Matt

Yota_Stomper

really? no reply's? I have a similar issue.. I wish someone would have chimed in.

warpigg

clicking is usally a cracked exhaust manifold and it can cause decreased gas milage and power also

mathyou

I had intended to post a follow up to this, but I guess it slipped my mind. *opps*

So the first thing I did was check the valve shims, 5 exaust and 1 intake shim were out of spec so replaced those. That felt like it brought back a bit of power, but the clicking sounds still persisted.

I had did an inspection of the exhaust system on my dads advice. Headers were a-ok, but found that on the connection from the headers to the pipe one of the nuts was missing. Replaced that and clicking went away, and power feels back to where it had been. Gas mileage is still a little low, but not as bad as it was. Its somewhere around 21-22 mpg on level freeways.

So I would agree with warpigg, check that your exhaust system real closely.

Take care,
~Matt

nitrowrench79

Run some Seafoam through the intake and let it sit while you remove the IAC and clean with throttle body cleaner (3M, CRC, etc.) Should bring back a little power. If not, check your compression again. If you still have a weak cylinder, pour seafoam in through the spark plug and let it sit a few hours. Lucas injector cleaner is a good idea every few tankfuls as well. Cheap maintenance.

vikkz

sounds like you got an exhaust leak, i got about the same truck as you and back when i bought it i had a cracked manifold. Little power on hills clicking noise, changed it with what i could find at the moment from autozone (dont buy from there) and it fixed the problem. Had good power no clicking nice and quiet. Just recently the manifold cracked again for the 3rd time so im going to order the mini headers from a 4runner 3rz. I know theres a thread on here about those headers they were on the 4runner 3rz with california emissions and someone gots the part number but last time i checked the dealer for it they had the headers for $132 which was cheaper then chepozone.

Yota_Stomper

Thanks for all the quick reply's I appreciate the help.

Sadly, this isn't my problem... I'm gonna start my own thread as I have a compression problem.

rokblok

iTrader: (1)

Deathcougar has mini header kits. At least he used to...