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Discussion Starter #1
cross posted from offroad 4x4 forums..

Been having some problems with my '95 Runner. Talked to the mechanic when it first started, but it was really intermittent - but it's getting worse.

I first noticed that sometimes at mid-acceleration, the engine would surge a bit (like it was losing power momentarily). But just happened every once in a while. Labor day, pulling the boat to the lake, after going 50-65 mph, coasted down to a T (with a sweeping corner that's actually a yield for a right turn), about 10 mph I got back on it, and it started misfiring badly. Floored it, and it downshifted and had full power. Noticed at the same time that the idle was different (and a little rough). On the vehicle tach, it was about 400-600. But other times it would be 1200-1600). The vehicle has been pretty prone to pinging, especially in the summer while running down the highway running the A/C.

More recently, if I run down the highway for a while (work is ~30 miles) then I slow down (for whatever reason, but it seems that the engine needs to get in the 2000-2500 range for it to do it), then get back on it (medium acceleration - I don't hotrod it) it surges and hesitates - but if I floor it, the problem disappears and it has full power.

Occasionally on a side street, 20-30 mph, mild acceleration I feel it stumbling a little. Idle is varied. Sometimes it will settle at 800-1000, but sometimes it runs 1500.

Minimally OCCASIONALLY when I first start it, it will hesitate after I've backed out of a parking spot - but only just for a second, then it goes fine.

Recently, last day or two, I've noticed that I wasn't getting a start - my brain registered it, but really didn't register it. Today it failed to start - and I reproduced it a couple times. What it does is Chrrr .. then nothing. Sounds like a dead battery ALMOST, but the volt guage is normal for starting. Kind of a "half crank" .. i.e. the piston made it to the top of the travel, then the spark came too early and stalled the starter motor. If I turn the key a couple times, it will get past it and start right up, and run fine (except the surging and hesitating).

I've learned how to drive it without it pinging - so I don't know if it is as much as it was.

This is the 3ZVE engine, had the head gaskets replaced last summer. Plugs / wires / cap / rotor replaced same time frame (May 05), as were the Timing belts and water pump (preventative maintenance since the T- belt and cover was off!).

Am not getting any "check engine" lights - it _does_ illuminate when you turn the ignition on and engine not started, so it's not burned out or disconnected.

The catalytic converter is .. err .. let's just say it's not plugged up. It's .. uuh .. free flowing with zero restriction. There is no water in the oil or oil in the water.

Any good ideas? I was leaning towards TPS sensor, but my mechanic seems to think that it would illuminate the engine light if it were bad.
 

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how the spark plugs look?

compression test ? vavles sticking from carbon? blowing smoke? using oil? fuel filter?
 

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Discussion Starter #3 (Edited)
Forgot to mention, sorry -

Replaced the fuel filter in September -> october this year.

Using oil is a stretch. It's leaking it. :) And it's leaking p/s fluid (will have mech look @ it -- I can't tell where it's coming from, even tried spraying it @ the carwash).

Have not looked @ the plugs. Last time I pulled the plugs they were a real [email protected]#$^ to reach on the passenger side...

Would the valves carbon up so close to when the heads were off? And the exhaust pitch doesn't change - it's feeling more like a miss than a compression problem..I did run a bottle of Techron through it in August (when it first had the problem). Didn't seem to help/hurt.

And have not performed a compression test. Cylinders had almost zero wear when the heads were off (I went down & looked at them when it was apart). At 183k the cylinders had no noticable ridge at the top. The driver's side towards the firewall cyl at one time had something bounce around in it (top of piston was slightly scored, as was top of combustion chamber, and the cylinder wall was a bit scored, but not enough to catch a nail in -- you could just see it.. Other cylinders you could almost see the factory hone..
 

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First thing I would do is to pull the rubber tube between the air cleaner and the throttle body and check it real good for cracks. As they get old, they get hard and crack and start sucking air. If it is cracked it is a dealer item. I tried using a used one only to have it crack in about a couple of weeks. They run about one hundred dollars.
 

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Discussion Starter #5 (Edited)
I'm going to replace the plugs today and see if that helps.

Not a fun job, to say the least!

Lots of stuff in the way. The 87 4Runner was MUCH easier to work on!!

:)
 

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Discussion Starter #6
Ok ... so here's what I found today.

Pulled a plug. Holy crap! It was WORN the hell out.

Electrode instead of being |_| looked more like |/

The outer part was thin, and WAY away from the electrode since it was so eroded away.

Bought a set of NGK's and put them in .. Seems to be running a LOT better now. Also changed out the negative battery terminal - so the computer was unhooked for about 30 mins .. and it's re-learning everything but is running stronger, more peppy..

Now I just gotta figure out what's wrong with the starter .. i think it has a commutator dead spot .. it just CLICKS and you can hear the gear engaging, but it doesn't spin.

The A/C compressor might be out (sigh) and the P/S system is leaking .. so it's got an appointment with the mechanic -- even though I can do it myself - I'm getting lazy in my old age..
 

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the starter sounds bad. just replace it. spark plugs son of a bitch!
 

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Discussion Starter #8
I will forever hate Toyota's design of the '95 4Runner for the back passenger plug.

Unless I was just being stupid and should have replaced it through the wheel well..

But getting it from the top, took me like 30 mins for that one damn plug .. once I got it out, I couldn't find the damn hole to put it back in..
 

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[QUOTE

Now I just gotta figure out what's wrong with the starter .. i think it has a commutator dead spot .. it just CLICKS and you can hear the gear engaging, but it doesn't spin. the P/S system is leaking [/QUOTE]

Search around for starter contacts and that will be your answer for your starter problem. The p.s pump is a likely suspect for the leak, also look at the high pressure line where it goes from the pump to the abs unit mounted on the pass frame rail. Seen alot of these leak.
 

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Discussion Starter #10
The plugs had about 20k miles on them. Didn't think about it until I pulled one out and it was really worn out.

The the starter contacts failed. I broke enough stuff pulling it out (the drain hoses, the soleinoid terminal that activates the starter).

Whoever designed the placement of the starter -- IMO needs to be SHOT, drawn and quartered.

Got a rebuilt @ O'Reilly for $69 (IIRC) with a lifetime warranty .. put it in, and it seems to be running well now .. except now the computer has to re-learn all of it's data..

Oh, and thank God for air ratchets .. the only way I'd have ever gotten the top starter bolt out ..

A few months ago, the truck shucked it's A/C belt. I bought a new one the other day and installed it - but didn't install the P/S pump yet .. I couldn't turn the compressor inside by hand (pulley spun freely), so I was a little suspicious. Confirmed. A/C compressor is locked up. Not 100% locked, but it turns about 1" then tries to kill the engine. Almost like it's hydro-locked .. is that possible with these?

I think I'll probably wait for the P/S pump until I'm ready to buy an AC compressor - just seems like a good idea to replace the two at the same time..

Gotta love 11 year old trucks :)

Even though I don't "off road" and it's my daily driver, I do use it to pull the popup tent camper (and my boat).. :)
 
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