car runs terrible after replacing leads/distributor cap

[venerableChicken]

Hi, really hoping someone can help me out here. Just replaced plug leads and distributor cap on my vs ss after having to get it towed home (cap was broken and lead from coil came off).
Now after doing this the car sorta started, but ran super bad, barely idling and backfiring real bad if any throttle was used. Put a timing light on it and timing was at around 10-12 deg atdc. Reset in diagnostic mode back to 10 deg btdc and car seemed to run nice. Took it out of diagnostic mode and the car would not start again!!!! put it back in diag.mode, it started again, timing still at 10 btdc and the car runs if i pull the paperclip out. So took it for a drive, seems to run alright then cuts out cylinders then runs great then bad etc thru the rev range, try to start again, will only start in diag mode still. no error codes showing, out of ideas.
Anyone got anything?? please?? am about to get a new rotor button to see if this helps

[muttley383]

Was the car running like this before the cap and lead change?
I would suspect a firing order problem. Probably have a lead out of order when you put them back onto the dissy.

[SP00KSTER]

if its not a firing order problem then check all your vacuum lines as you may have knocked one loose and this can cause the engine to run ruff.

[venerableChicken]

leads are in the right order, checked like 5 times now, and also marked both ends of leads to make sure. Have tried 2 sets of new leads now, new rotor button new cap, plugs less than 10k old. Leads and distributor cap changed as old cap cracked and leads were old, but the car was running well beforehand. Perhaps vacuum leak but cannot see any loose connections anywhere

[BlackVXGTS]

I don't see how changing a distributor cap and leads would have caused the distributor to move sufficiently to change the timing from 10 deg btdc to 10-12 deg atdc. Did you notice that the distributor was loose when you changed the cap? Have you checked to see if any error codes have been set?

[Jxw]

got a spare ign module to try? maybe yours copped a ht belt when the old cap cracked and the lead fell off, i've seen similar happen on a sb chev but that actually fried the module good n proper from the ht spark that fed back through it...

maybe something to try if you can get your hands on one to borrow and see if that makes any difference or try yours in someone elses car as a last resort.

[venerableChicken]

Hooray I have it working again!!!! Finally!! Turns out the coil was shagged. I thought it may have been the ignition module too Jxw and luckily a friend had a spare i could try but that was not it. In the end i replaced the leads, distributer cap, rotor button, ign module and finally the coil. But not all bad as the car is running a lot sweeter now than it did before!

As for the timing blackvxgts I'll be beggared if i can work out how the hell that changed as the dissy was definately not loose. No error codes came up anywhere along the way