94 22RE, Diag. Code 25, Hesitation, Depth of Computer Diagnostic Through Connector - Toyota Nation Forum : Toyota Car and Truck Forums

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post #1 of 3 Old 05-31-2007, 06:31 PM Thread Starter
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94 22RE, Diag. Code 25, Hesitation, Depth of Computer Diagnostic Through Connector

94 22RE, Diag. Code 25, Hesitation, Depth of Computer Diagnostic Through Connector

I have a 94 2WD with a 22RE, 5 speed, and 218,000 miles on it. I am having drivability issues as well as a persistent check engine light that shows a code 25, air fuel ratio lean.

I was having severe hesitation problems at low RPMs after running until warm then shutting off the engine for even a few minutes and starting it again. It felt like it wasn't running on all cylinders and would sometimes stall. The lower the temperature the worse it got.

I took it to a Computer Diagnostic shop that supposedly could plug into the trucks diagnostic connector and evaluate it deeper than just the generalized code 25.
They concluded that the EGR valve was bad, that the throttle body needed cleaning, that there was a slight leak in the number four cylinder intake manifold (they said the manifold might be cracked, “this engine has had problems with that”), and that the fuel filter might need replacing even tough it wasn’t showing a problem it is the original. Estimated parts and labor $685 less the replacement of the intake manifold with the pretend crack.

The intake manifold is probably a product of my foray into the world of high finance two years ago when I had the distinct honor of being allowed to contribute to the building of an additional wing of a local Toyota dealership when my timing chain had to be replaced ... $2000. Six months later I was back to get the exhaust manifold bolts re-tightened. (When doing expensive, shoddy work, why discriminate against the intake manifold?)

I took the Diagnostic shops advice and replaced the EGR valve & gasket with a new one from AutoZone, $140. The old EGR valve seemed to leak a little when I blew into it.
I sprayed the hell out of the throttle body with some cleaner, didn’t use the toothbrush however. I found that the intake manifold bolts were a little loose & I tightened a couple of them. I’ll do the rest later with a torque wrench. Possibly this is the source of the “crack”.

At first this really seemed to do the trick. The hesitation was completely gone, my check engine light stayed out and my gas mileage improved three or four mpg.
After about 4 days the check engine light came back on. The hesitation is much better but the weather is warmer now, and the gas mileage is now only about 2 mpg better.

Recently when I flipped the cap on the trucks diagnostic connector I found that the grease over the connection points was not disturbed. I don’t think the last place I went to plugged any thing into it.

Are advanced diagnostics available for this truck plugging an analyzer into the Diagnostic Connector? Can they get more information at that connector than just an error code?

What kind of info is available through the diagnostic plug in?

Could the oxygen sensor be causing this code? How can I check it without replacing it?
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post #2 of 3 Old 06-01-2007, 07:36 AM
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This link is from the free online manials at the top of this section for future reference. It is actually for a 93 but it is the same thing.


Go to the MFI System section. There is a section there that explains how to test the O2 sensor. It is a simple ohm meter test.

I do not believe there are any "advanced diagnostic tests" for these vehicles. That would be more like the OBDII systems. These just give the codes that you compare to a list in the service manua', as far as I know.

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post #3 of 3 Old 06-01-2007, 08:43 AM
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Your problem sounds like it might be a vacuum leak or a leak in the intake tube between the VAFM & throttle body.

STOCK '94 DLX XtraCab 4x4, 5 spd, 3VZE, 270,000 mi.

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