Engine Misfire 3.4L

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- Dave and Daphne
  
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posted
19 years ago

Wed, Feb 2, 2005 4:54 PM

I have a 1999 Tacoma 3.4l that has had a miss for quite awhile now. Plugs and wires have been replaced with no change. Just went for a ride with the local mechanic who hooked up with an anylizer and found that one bank of cylinders is the source of misfire, Cylinders 1,3,5 with number 3 being a little worse than the others. No check engine light has ever come on. It is worse after startup but will still miss on occasion when completly warm. Idles fine and cruises generally OK, but under heavy load or a little behind the power curve it breaks down badly. Anyone else with similiar problems or solutions.

Thanks Dave

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- Mike
  
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posted
19 years ago

Thu, Feb 3, 2005 1:27 AM

How many miles on it ? How long has it been acting up ? Is it getting worse ? Are you loosing any coolant ?

When you say it is worse after startup it kinda sounds like a leaking head gasket. I would do a compression test first. If the compression test and head gasket are ok you need to figure out if the problem is in the fuel system or the ignition system. It could also be a bad O2 sensor for that bank of cylinders. You should be able to narrow it down some by driving it with a scan tool hooked up and look at all your sensor values. Lets us know what you find.

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- phillip91
  
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posted
19 years ago

Thu, Feb 3, 2005 11:06 AM

I have 97 3.4 same problem. Most of the misfires from #3. I finally checked the compression and the left bank around 150 the right bank >100. My engine has 268000 mi, none of them easy. I have never had a problem till now. Still running factory clutch. Used two sets of plugs, two timing belts,one set of wires. I'm sure a head gasket would get me going but I cant see going to that much trouble given the miles. Bought another engine out of totaled 4runner with 41k. Start the swap today. Hope yours will be a lot simpler.

let me know what you find

Phil