My car today started acting all kinds of crazy, the car hesitates and bucks, and the tach just is going crazy, while driving at steady RPMs it jumps around sometimes jumping to 7k and staying there for a sec other times just jumping around. Now this is just the tach, the motor doesn't vary RPMs they stay constant. So I limped the car home and pulled the codes and its throwing a 3 and a 7 (map electrical and TPS) and 20 and 21 (electrical load and VTEC soleniod), the car was running great just a few days ago and I am stumped can anyone help me please.

 

ok well changed the distributer and it does not hesitate anymore, i was thinking that my field vtec controller is hooked up to my rpm signal, if a wire is touching metal then would that make my tach jump. Also i do not think it is my disributor because the motor runs fine, do you guys think it could be a connection between the tach and the ecu. Also my field vtec controller reads rpms to and they jump just like the tach, help please, driving me crazy.

 

please help

 

I also do not have a ground the the t-stat housing like people say i should, but if that was the case wouldn't my tach have been jumping in the first place, and not just starting now.

 

no one

 

your coil is bad. confirm by testing it out with a multimeter. Measure the resistance.

My tach jumped too until I changed the coil.

 

Bad coil. I had the same problem for a long time and i finally replaced my coil 2 weeks ago and it runs smoother than ever, never had a problem again and the response is a little better also, but hey now its just another excuse to put a cool lookin ignition coil under ur hood lol have fun dude! let me now how it goes, Peace