MK2 8v digi(pissmeoff) - HELP - revs drop regularly when held constant throttle

[courtz1976-2dr]

OK have an update, ran through all diagnostics available on digifant that I could find, interesting after unplugging 02 + knock sensor and running around for a while and then plugging back in seems to run better. also looked at nipple that connects to fuel pressure regulator and was a little gunked up (only very minmal oil)

. Things seem to have improved but there is still slight hesitations between 4800- 6500 again like a miss. Time to replace the rotor button, leads and maybe coil. ran all daignostics for ignition module. There was a test that I did that is as follows

measure between low tension circuit and should read 2 volts and drop to 0, when unplugging ingiition control module. Mine stayed at zero (with ignition on) maybe I have done this wrong.

Any other ideas??? no vacuum leaks.

[courtz1976-2dr]

Ok I would like to buy

new knock sensor suit rv engine.
new o2 sensor
coil
rotor

Anyone help out with these part (pref new)

Cheers and Regards,
courtney./

[Jezza8v]

Hi there everyone

Im hoping someone can point me in the right direction with a new problem

when I hold the throttle steady at any revs the revs drop regularly but always back up to relative to throttle

ie hold @ 2000 smooth - drop - smooth up to 2000 - drop
hold @ 3000 smooth - drop - smooth up to 3000 - drop etc etc

grrr

Greetings from the UK (near Oxford), pleased to have found this site as this topic has the only reference to our problem, the car is an 89 Mk2 8v digi. We have this exact same issue which developed about 2 weeks after running the car following a rebuild. Repaced MAF sensor and checked throttle switches but no fix, the car is now undriveable due to this problem so getting desparate. I'm curious as to whether you ever found the source of your problem? Thanks in advance, Jeremy.

[benough]

try germanautoparts.com

Otherwise give Brian from GTI Imports a call.

[Jezza8v]

OK, just in case anyone out there gets a similar problem, we have fixed ours. We replaced the ecu and all is fine, the problem was that due to an internal short or break in the ecu (to be determined) it was stuck permanently in 'idle' mode so that it was constantly performing the VW specified 'surge test'. If you get this problem, to check, just disconnect the blue temperature sensor, (the engine will rev up a bit) and then see if the engine still surges between 1500 and 3500rpm, if it does not not then the either the idle swicth circuit is shorted on or the ecu has a fault. It is easy enough to check the idle and WOT switches. Regards Jeremy.