[Gotenham]

97 sierra with vit 94 g16b conversion efi 16v

having some power problems. First off the throttle has no power after about 20mm, the car kinda bogs down with no energy, .she idles fine when first started and can be reved with no load easily.
I also noticed that after a short drive the idle revs seek like crazy, going from 1.5k to 2.5k then dropping back to 1.5k again and repeating, both with the clutch in and when in neutral..

At first i suspected the TPS but all continuity is good, and the sensors resistances are fine too, with a smooth increase in resistance as the throttle is increased that is within the manu. specs
Next i thought it could be the vacuum lines so i double checked those and found the EGR solenoid was stuck and couldnt actuate so after a failed reconditioning with wd40 i replaced it with a swift one i got from a wreckers, but after a drive it still hadnt solved the problem..
I did a compression test and all cylinders are sweet

Has anyone heard of these symptoms and what could cause it/what to check next?
Im thinking were not getting enough fuel?
Cheers

[christover1]

It could be cooling system issue,
an air lock, thermostat,
loose wires or plugs on sensers,
head gasket (hope not)

has temperature been any different

[Gotenham]

also forgot to say i ran a CEL diag and came back fine (12 which is all good)..

Temperature hasnt been out of the ordinary..
Cheers for reply

[christover1]

I had a long time blocked egr on a past zook,
it blocked up right through the head,
as extractors had no provision for egr.
It ran fine, but of course it wasn't efi it was a carby.

No idea if egr could be your problem,
but it may be carbonned up if its been a while.

[Gotenham]

found the solution..it was a degraded fuel hose on the pump assembly in the fuel tank..all the pressure was being lost back into the tank..might be something to check if you have the similar problem..its all on here http://auszookers.com/forum/viewtopic.php?f=4&t=33469