Misfire or poor ruuning after tune up

1994 LEXUS LS 400
289,000 MILES
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STEPHENP
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I just replaced the plugs, distributor caps and rotors and coils. The car starts great but once it comes up to temp, it feels like it's missing. Drivability is okay at lower rpms, but there is valve chatter at 2500 or above. Wants to die at idle. It runs much better with the AC on.

There is spark to all cylinders. What did I do to cause this? It was running ok before the parts change and the problems seemed to start when I replaced the parts on the driver's side distributor.
Mar 18, 2012 at 10:04 PM
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RASMATAZ
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Are the sparkplugs gapped to specs and firing order is correct-all connections are firm/tight?
Mar 18, 2012 at 10:07 PM
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STEPHENP
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Yes. All plugs were NGK OEM and installed with 22 FT lbs. Plugs were gapped to 0.044 per spec. All plug wires have been double checked for correct routing. The rotors were double checked to make sure they are correctly positioned.
Mar 18, 2012 at 11:33 PM
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KHLOW2008
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  • ASE Certified Mechanic
Did you test the plug wires? Have them ohmed out to see if any is out of specs.
Mar 23, 2012 at 1:22 PM
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