[TR] Fuel starvation in my TR4 - Report back

[Dean Mericas]

Original message:
<Symptoms:
- Car runs well and with full power for a while after start-up.
- Loss of power and what feels like a miss under load after it's been driven
a while.  Going up a long hill seems to trigger the stumbling.  If I let up
on the throttle, it smoothes out.  Sometimes it drives well again for a
while.
- Problem seems to be worse when it's really hot out (I live in Austin),
although it also happens on cool mornings
- Engine idles smoothly even when it's not running well under load.>>

You guys have been great in coming up with ideas.  This is what I've done so
far (without any apparent effect on the problem):

- Swapped out the coil with a good used Bosch unit
- Swapped out the Pertronix ignitor unit with a set of points, gapped them
to spec, and set the timing.
- Checked the advance mechanism, and it does.
- Checked the spark plug gaps
- Checked the oil level in the carb dampers (ZS carbs)

Other suggestions that don't seem likely:

- Water in the gas.  The fuel pump bowl is absolutely clean w/no trace of
either water or debris.

- Hung up fuel valve in one of the carbs.  It seems like gravity would tend
towards a failure mode with too much gas not too little.  I'll probably
check this if all else fails.

- Kink in one of the soft gas lines.  I looked at the various sections and
they all appear OK, at least superficially.  I may go ahead and replace them
all if I end up draining the fuel system.

I'm open to other suggestions.  Is there any chance that some valve train
issue, such as a weak or broken spring, or a burned valve could be causing
these symptoms?  It seems unlikely since the problem is intermittent.

I'm thinking that he next step is to drain the fuel tank and back blow the
fuel line to convince myself that there is nothing clogging it.  I'm running
out of ideas if that doesn't solve the problem.  This car has been
remarkably simple to maintain and reliable in the 19 years that I've had it.
This loss of power at high speed problem is getting pretty frustrating.

Dean Mericas
Austin, TX
1965 TR4 / 1974 2000 GTV / 1976 Giulia Nuova Super