Random miss for part of a second. 3.4L DOHC w/ Auto

[Scott205]

Hey guys,

 

This is my 92 Cutlass, did the engine swap a few years ago , so it is 92 wiring, computer (with Ben's chip) and the original auto (with a rebuilt torque convertor).

 

Occasionally I am experiencing a complete miss in the engine. Usually when I am at WOT passing someone, as the RPMs are up around 5500-6500, it will just completely cut for a brief partial second , usually a couple or three times and then downshift and be fine.

 

However a couple of weeks ago I was traveling long distance and about 3 or 4 hours in the trip it did it in 4th gear around 70-75mph. The car was pretty loaded down with a bunch of moving boxes.

 

I think what it is: A coil is causing sparking on the DIS, and it sends the signal to this DIS to shut down, but then it doesn't happen long enough to completely stall the engine, just drop the RPMs a couple of 1000s

 

Is there a way to test the coils? I have an extra set of coils and a DIS, but last time I had problems, I know one of the coils on it is bad becuase it would start, then immediately shut down between 5 to 60 seconds.

[AL]

You can take a miltimeter and check the ohmic resistance of the coil but they are common to fail on a 3.4 because of there location... Even if the resistance tests ok they could still be bad... I use a spark tester with gloves on and attach it to the end of a plug wire and start the car and I keep opening the gap to see how strong the spark is

[spiderw31]

Also look for arcing. You won't be able to check under load, but look under the hood while it is running in the dark and look for arcing / spark anywhere by the coils an wires.

 

I think you are on the right track with the coils / ignition.