Re: 33 dual coils question

Posted by Tim Cole On 2016/3/23 17:20:44

There should be two rubber doughnuts on the plug wires to keep them from flopping around.

Those cars are notorious for small vacuum leaks in the power brake system, leaking Bijur pump diaphrams, and cracked wiper hoses under the cowl. What you get are random misfires. A vacuum gauge will not detect them. What happens is the lean mixture affects a couple of cylinders.

The 4.0L Ford does the same thing. Manifold vacuum is great, but the idle quality sucks, the fuel trim is sky high, the idle speed is high, and the check engine light is on for a lean code. You can't diagnose it with other than the TSB from Ford that says to replace the lower manifold O-rings.