waltah
10+ Year Contributor
- 368
- 156
- Mar 2, 2011
-
fairfield,
Virginia
'95 GST, auto, 150k miles but engine probably less, bought about a month ago, runs very well except when you get to about 7 psi boost in any gear there's a groaning noise and loss of power. Boost does not fall -- it'll go right on up to 15 psi.
Could be a very regular miss -- I've never had a waste spark car before so I don't know what a single coil failure under load might sound like. I did swap the transistor assembly -- made no difference. Doesn't seem likely to be a mixture problem -- it's too smooth and regular, also the plugs look fine and gaps are correct. I wonder about a clutch chattering in the transmission but what clutch would be in action in all gears? Also, clutch problems I've seen have all been totally silent slippage but those were all on the smaller transmissions.
Additional symptom, possibly related: There's an occasional single or double 'thunk' miss when I come to a stop light. Sometimes doesn't happen at all, sometimes happens a few times before the light goes green.
If possibly a coil failure is there a way to swap coil packs without removing the fuel rail? Manual says 'unbolt transistor and take out, unbolt coil pack and take out' and that's it. But my car has the Diamond F648 assembly and I couldn't figure out how to get it out of there without removing the rail. Hopefully I'm missing something obvious ???
Could be a very regular miss -- I've never had a waste spark car before so I don't know what a single coil failure under load might sound like. I did swap the transistor assembly -- made no difference. Doesn't seem likely to be a mixture problem -- it's too smooth and regular, also the plugs look fine and gaps are correct. I wonder about a clutch chattering in the transmission but what clutch would be in action in all gears? Also, clutch problems I've seen have all been totally silent slippage but those were all on the smaller transmissions.
Additional symptom, possibly related: There's an occasional single or double 'thunk' miss when I come to a stop light. Sometimes doesn't happen at all, sometimes happens a few times before the light goes green.
If possibly a coil failure is there a way to swap coil packs without removing the fuel rail? Manual says 'unbolt transistor and take out, unbolt coil pack and take out' and that's it. But my car has the Diamond F648 assembly and I couldn't figure out how to get it out of there without removing the rail. Hopefully I'm missing something obvious ???