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post Dec 12, 2013 - 5:50 PM
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PaukST



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So, about 3 weeks ago my 94 ST started getting a misfire. Initially, it was only under mid-heavy load, like going up a hill at relatively low revs. I replaced the spark plugs and it got better for a few days, then went back to the occasional misfire. However, a few days ago it suddenly got way worse. I pulled up to a stoplight, but when I went to take off, it would barely go. It's nearly undrivable. It's pretty much a constant misfire now. It seems to be cylinder #2. It tries to die if i pull a spark plug wire/unplug an injector from 1, 3, or 4, but nothing changes when i unplug either from cylinder #2.

I had changed out my spark plugs and wires probably less than a year ago. I rebuilt this engine June of last year, and have had a VERY slight miss with this engine all along. I assumed it was due to the ever-worsening crack in my exhaust manifold (located closest to the cylinder #2 exhaust port).
So:
---Rebuilt 18 months ago
---Replaced spark plugs about 2 weeks ago, the old ones weren't broken or particularly noteworthy
---Replaced spark plug wires within past year
---Switched over the injectors from my other 7A-FE thinking one may have been clogged, no change

Anyone have any ideas? Advance tells me they can't check the CEL code on anything pre-96.

Second edit to add that I replaced my distributor cap/rotor around the same time as my spark plug wires. I took the dist cap off today and cleaned up the contacts, they looked fairly bad again. Unfortunately that changed nothing.

This post has been edited by PaukST: Dec 12, 2013 - 6:15 PM


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1989 Celica ST Automatic "King Cobra" -- 2005-2006
1994 Celica ST 5-speed "King Cobra II" -- 2011-????
 
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post Dec 12, 2013 - 8:52 PM
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Special_Edy



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Use a multimeter to check primary and secondary resistance on the coil.

Remove the valve cover and check the valve shim clearances with a set of feeler gauges. They should of been checked when reinstalled, they tend to get smaller gaps till the valve is being held perpetually open
post Dec 15, 2013 - 4:12 PM
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Island_Racer

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QUOTE (Special_Edy @ Dec 12, 2013 - 9:52 PM) *
Use a multimeter to check primary and secondary resistance on the coil.

Remove the valve cover and check the valve shim clearances with a set of feeler gauges. They should of been checked when reinstalled, they tend to get smaller gaps till the valve is being held perpetually open


May i ask what the correct range is, for the resistance that shud be observed in the plug wires (3rd gen 3sgte)

This post has been edited by Island_Racer: Dec 15, 2013 - 4:13 PM

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