If a tachometer is connected to a coil and is reading out the wrong revs and the settings on the tachometer are correct what makes this happen??

Also the car violently holds back like the injectors have cut out at what it says to be 4500 to 5000 rpm which is definately not right and I reckon its actually about 3000 rpm.

If I turn the lights and heater on it will do this at even lower revs

Please help as I have replaced the coil and now don't know what to look at

 

what car is it??

 

cavalier SRI

Don't worry I am a ford man its just a runaround

 

ermmmmmmmmmm possible battery or alternator problem???? sounds a bit if you have a big current drop , lights on etc...

 

Its confusing me cause it reading 4500 rpm in 5th at bloody 90

Somin tits up!!

The batt starts the car fine.

It does it in every gear so have to change gear really early, also won't go over 100 If I go to the point where it cuts back too many times it dies aswell like it just run out of fuel then I quickly turn it off and on and it fine

 

ermmmmmmmmmmmmmmmm

 

Would timing affect this?? I really running out of ideas

 

Any one else got any ideas

 

bttt

I changed the coil and is still the same What could be causing this??

 

 

alternator/battery or bad earth, check voltage across battery and ecu when running