2001 Toyota 4Runner 2001 4Runner - Head gaskets and Injecto

Tiny
SBOWL1
  • MEMBER
  • 2001 TOYOTA 4RUNNER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 96,000 MILES
Problems with my 4runner. Had the 90k service done. Replaced plugs (6), water pump, timing belt etc. A couple of weeks later it ran rough and the check engine light came on. I took it back to the mechanic and they said the injector wires shorted and needed to be replaced. It ran fine for a few weeks, but then I almost ran out of gas and it immediately started running very rough and the check engine light came on. I took to the same mechanic and they scanned and said there was a misfire code P0300 and that one of the fuel injectors was clogged so they replaced it. They indicated when you get real low on gas, the engine may suck up sediment on the bottom of the tank which can clog injectors etc. I used Techron as they said the other injectors might go bad. Three weeks later, same problem, rough running, check engine light, same as the two times before. This time they scanned and another misfire code of P0300 so another injector was bad. They had to tear into the engine to get at it, expensive, and we agreed they would replace the other two injectors on that side at the same time since they had access to it and it seemed like the injectors had issues. Thought I would save money in the event the other 2 went out in the future. The bad injector seemed to have been fried from running hot.

Three days later, the exact issues came up again. This time they finally determined the head gaskets were bad. There was leaking of coolant which crystalized and then acted a s a sand blaster, damaging the plugs. Lots of carbon in the engine etc. The truck had not been running hot.

They said the timing belt was fine. They specifically checked. They said if it was a timing belt issue it would have been very sluggish. After calling numerous shops and Toyota, they determined it was a gasket leak that was between No. 1 and No. 3 which led to the coolant being in the engine which led to all of the carbon. They resurfaced the heads. The valves were OK so they don’t think the issues were caused by the timing belt. They did adjust the valves. They also replaced all of the plugs.

Seems like the initial 90k service may have led to all the problems since they were dealing with the water pump etc. Seems like they may have simply misdiagnosed the injector issue (spark plug wire issue?) Twice, but that was about $1,200 worth of misdiagnoses. Odd that it ran rough immediately after almost running out of gas.

Seems like at best, they misdiagnosed the problems 2-3 times and at worst, their original work caused the issues. Common for a 2001 Toyota 4 Runner to have bad gaskets, injectors? Is there any way I can legitimately establish any of that? What do you think? Just a series of problems that all started right after the 90k service.
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Friday, July 25th, 2008 AT 3:43 PM

3 Replies

Tiny
JACK42
  • MEMBER
Hm, The newer (3.4L) Toyotas didnt have near the head gasket problems that th eolder (3.0L) did. Sounds like they were guessing to begin with. P0300 is a generic misfire code, it doesnt point to a particular cylinder.I personally can count on one hand how many Toyota injectors I have seen go bad. Does it still do it? I would have leaned toward a bad plug, wire or ignition coil. The coils on those engines feed 2 cylinders, so if it makes one cyl show a miss it will usually do it to another one. Did they charge you for that valve adjust? That is a hydraulic lifter/follower in that engine, there is no adjusting other than the installed height of the valve when a valve job is done.
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Saturday, July 26th, 2008 AT 8:09 AM
Tiny
SBOWL1
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O injector problems since I've gotten it back (5 days). The first problem after the 90k, their solution was to replace the ignition wire set and one plug that was damaged. That worked for several weeks until the odd gas issue (same rough running and lights).

Assuming one bad gasket that was simply defective, do you think all of the other issues, e.G. Injectors, ignition wires, were a misagnosis? Would the bad gasket have caused any/all the issues post 90k service? Just looking for some opinions.

Do you think a screw-up on the 90k service, (Timinng belt, water pump, thermostat, belts, hoses, spark plugs, air filter, service transmission, pan gasket filter) could have caused any/all the subsequent problems (gasket)?

I'm looking to get a refund on some or all of the subsequent charges so I'm looking for likely explanations. Seems like a huge coincidence that all of these issues happened soon after the 90k service.
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Monday, July 28th, 2008 AT 1:56 PM
Tiny
JACK42
  • MEMBER
Sounds like some misdiagnosis to me. If it was between 1 and 3 they would have 2 misfires to begin with and it would have run rough all of the time if it was passing coolant and or compression back and forth between 2 cylinders. Head gaskets dont temporarily repair themselves, they usually run rough in the morning or after the car has been run and cooling system pressure builds up then the vehicle sets and bleeds the coolant into the cylinders. They dont run ok for weeks then start to miss again
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Tuesday, July 29th, 2008 AT 7:30 AM

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