When my car idles, the tach jumps from 600-900 rpm's. I heard it was the BAC valve and/or throttle position sensor. It also does it when im in a high gear and a low speed, ie. 35 and 4th gear, then i hit the gas and it jumps about 5-700 rpms, otherwise it's fine.

Is it the tach floating or do your rpms actually flucuate?

The engine and other gauges are just fine, the tach jumps. Performance and idle is just the same. It did it a while ago before i got my clutch changed. But it just returned and always catches my eye at stop lights or accelerating in a high gear. https://www.nopistons.com/forums/pub...1047683473.gif

it could be an intermittant connection in the tach circuit.



mike

How the !$#& am i going to locate an intermittant connection https://www.nopistons.com/forums/pub...1047683561.gif ? Yet fix it? Thx for the help Mike https://www.nopistons.com/forums/pub...1047683894.gif

well, look at the wiring diagram and start by making sure all the connectors are tight and in good shape



mike

You might also want to hook up a timing light to the trailing coil wire, tape the trigger

down and aim it inside the car. Then sit in the car where you can see both the light and the tach. Start the car and watch both.



If the tach jumps with the light steady, look for breaks in the wiring loom after

the trailing coil.



If both jump/act funny at same time, look for breaks between dist and coil.

Especially near where it goes over the A/C compressor.



Hope that helps

Raul

I just picked up a haynes repair manual today. First of all thanx raul and mike for the help https://www.nopistons.com/forums/pub...1047683894.gif but i noticed today my car was a little degraded(kinda hard to notice, maybe just the sea foam i put in with this last tank) in performance. Sometimes it's hard to tell, but when your oil pressure/level gets low can you feel degraded power and response? Maybe i have blown an apex seal. How could i tell for sure besides a compression checker? Is it possible to remove/relocate the 6 colored solenoid valves on top of the engine block? Cuz i think they're wack as hell. https://www.nopistons.com/forums/pub...1047683771.gif

usually if your apex seal is blown the car will have about 32hp, and wont idle



mike

where is the apex located because my car wont idle