undrivable once warm-help

[wacjac]

i thought i had cured a "misfire" once warm, with the changing of coil and ignition module.all was ok for a week or so, but now the problem is back worse than ever. car is fine for a few miles, then once warm the slightest touch of the throttle,sends the car kangeroo'ing terribly with the rev counter bouncing up and down..only got the car home by putting in 3rd and keeping totally off the throttle. car had new magnecor leads prior to me purchasing and has lucas rotor arm. any help or suggestions would be appreciated .
cheers in advance joe

[blitzracing]

If the rev counter is playing up, (as in really jumping about down to 0 and back) the fault will be the trigger system to the coil or the 12 volt supply side. Double check ignition amp wiring, and also suspect the trigger wires from the magnetic trigger head in the dizzy to the amp. (These move with the dizzy diapham and can fail as the timing plate moves depending on throttle possition.) Its also possible the power feed to the coil is failing in some way, or possibly bad earths.

Edited by blitzracing on Monday 19th March 12:38

[wacjac]

blitz,
Tho i suspect the problem is somewhere in that region, when i bought the car, it had a "power amp" fitted. The car was fitted with this and a tornado chip by a v8 'specialist' in norfolk. Not sure whether the original amp is still supposed to be on the car,but it is and this is what i replaced a few weeks back along with the coil. i now assume that the 'fix' that lasted a week or so, was more about the wiring being moved whilst fitting. not sure how to get rid of this "power amp" or if it is doing more harm than good.

[cureton]

Once my mechanic convinced me to fit one of these "power amps", a rectangular grey box. Well, it cured a problem which was never there but after some 3 years I noticed these intermittent cut-outs. The power amp showed bad corrosion inside so changed back to the original amp and no problems since.