Still got a jolty running engine ,?

[pud]

HI, i have now changed the plugs , plug leads, rotor arm , distributor cap, but the engine is still running jolty, but if i put my foot down i can power through the jolting and the engine goes very well and fast, what do i do next , ?

[ossiblue]

It will be a great help now, and in the future, if you edit your signature and put your car's year and model in so everyone will know how to address your problem. I remember your earlier posts, and you have a 1975 911S with CIS, correct?

Since you've checked out nearly all the ignition components, save the CDI and coil, you've nearly eliminated one area of fault but until you can swap out the coil and CDI for known good ones to see if the problem goes away, that will always be in the background. Have you been able to test for erratic spark with a timing light?

Next, in order of ease of diagnosis, IMO, would be:

The fuel delivery--specifically a lean condition. You will need pressure gauges to test for warm running (control) pressure which is the next likeliest culprit--too high warm control pressure leads to a lean condition which could cause your symptoms. Do a search for CIS pressure test to get an idea of what is involved.

Following that, a faulty injector could also be involved so pulling the injectors and running a test for volume and spray pattern should be done.

The results of these checks can help determine where to go next so continue to report what you do. Perform one check at a time and report all results.

Finally, a vacuum leak(s) in the CIS could also be involved, but these can be tedious to track down.

[pud]

hi thanks i will carry on with what you have said, thanks

[T77911S]

i see you have 3 threads open on this subject. its best to keep it to just one.