I have an 88 Formula automatic that recently got a full set of new injectors, plug wires, rotor and cap, plugs. the tach was really jumpy before I got the new injectors, but today I noticed it jumping under load again but not as bad, does anyone have an idea what would cause this besides tach filter?

Iffy filter or tack itself are good bets.
Plug(s) to back of dash and/or dash circuit board can be problems too.

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quote Originally posted by theogre: Iffy filter or tack itself are good bets. Plug(s) to back of dash and/or dash circuit board can be problems too.

I'm not sure, I'm going to jump the filter and see what I get. it wasn't jumpy when I first got it, and its just upper RPMs under load.

[This message has been edited by Harley95 (edited 12-19-2014).]

just checked again cylinder 1 seems like its fouled a plug, I wonder why.....

You ever find out the problem with jumpy tach under load?

Possible pick up coil?

Just what I thought also. I had the same or similar problem. Changed out everything in the ignition system. Still had the problem and changed out the pickup coil and problem solved.