>I am the proud owner of a '79 Spit which has one nagging problem (that I
>know of). During freeway driving, at about 60mph and 3500rpm in 4th
>gear, it starts missing. Stepping on the accelerator won't get it above
>60mph.
>I've checked the timing (it seems to idle much better somewhat advanced
>from what the specs call for).Also the problem doesn't seem to occur at
>3500rpm in the lower gears.
>Any advice, help or a nudge in the right direction would be greatly
>appreciated!
Wow, it's the day for mystery problems just like mine! I have the same thing,
but
at ~73 mph (~4200 rpm), only in fourth and only after about 10 minutes driving
that
speed. It also seems to go away from time to time. Of course, I generally
don't
drive for ten minutes at 4200 except on the highway in fourth...
The problem seems to be fuel-related in my case. If I slow down by 10 mph and
drive for a few minutes, I can speed back up again for a while. Then it
happens
again a few minutes later.
There are no strange noises. It's not suspension or brake related. I have
pulled
over and checked the coil - it's warm but not hot.
I haven't yet pulled over and checked a plug. I have had multiple things
contribute to this. I definitely had float and needle-valve problems at one
time.
I believe those are fixed. Vaccuum problems affect it too. I had a leak at
the
EGR connection between exhaust and intake manifolds. This made the problem
occurr
at lower speed.
My belief is that with all this smog stuff on the car, a vaccuum leak has a
much
more profound effect on the mixture than it would on a less
vaccuum-driven-wierdness-intensive vehicle.
So check for vacuum leaks, and check your fuel system/float bowl.
Do let me know if you figure this one out, cuz I've been trying to solve it for
almost two years.
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Alan Coleman (alanco@sybase.com)
'79 Spitfire
'64 TR4
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