Please help!

[8v Grunt!]

Tried using the search function, but could not find anything related to my problem. 89 8v. Intermittent problem. It happended today but hasn't for a couple of days. At junction in 1st gear with foot on clutch ready to pull away. Revs decided to climb and drop on their own, all over the place. I tried blipping the throttle to try and steady her but no joy. When i pulled away i had no power and really struggled to keep going. I was trying to rev the car but it would not respond to anything i did with the throttle. After about 5-10 seconds it went right back to normal and off i went. I have also noticed that occasionally the car misses a beat on acceleration. Not sure if these are related at all. I have also recently had water in the fusebox and had to change the ECU relay. Any help would be much appreciated. 
 

[Diamond Hell]

When was it last serviced?  Have the ignition components like the leads, cap, rotor arm and plugs been replaced this decade?

Unclip the fuseboard and pull a couple of the block connectors off the back so you can see if there's any corrosion trashing the connectivity.

Also make sure there aren't any of the vacuum pipes around the engine bay that have perished.  Vacuum leaks on an engine can play havoc with the throttle response. 

Get some carb cleaner and hose the Idle Stabilisation Valve out to make sure that's working right.

Once you've done that get a 1/2" paint brush and use that with the carb cleaner to clean the throttle butterflies - if they're sticky and there's a lot of deposits stopping them closing properly things tend to act up.

[8v Grunt!]

I have replaced the rotor arm, dizzy cap, plugs leads about a year ago. Nothing wrong with spark as she always starts first time. I regularly clean the ISV, throttle body and butterflies. I will check the relay for corrosion. I also keep an eye on the vacuum pipes as i know these are important for the correct running of a digi. Just changed the ignition amplifier and this has made normal running and idling a bit smoother. Got a second hand dizzy. Any chance it could be dizzy related?

[8v Grunt!]

I also have another issue. I think it is all related. When driving the car from being left overnight when pulling away it feels like and sounds like it is missing or something. At lower revs there is a strange noise like it isn't running on all cylinders and no power or acceleration, then all of a sudden it clears and all is well again. It will do this until either the engine has warmed up or the moisture?, if there is any anywhere has gone. It is worse when it has rained overnight. Very disconcerting when you try and pull away from a junction and you get nowhere generally being stuck in middle of road feeling like a right plank! If you pull away as gently as you can you can just about get away with it. Please help me as i love my 8v and she puts a smile on my face everytime i drive her but doing my head in at the mo.

[ToddyGTi]

I also have another issue. I think it is all related. When driving the car from being left overnight when pulling away it feels like and sounds like it is missing or something. At lower revs there is a strange noise like it isn't running on all cylinders and no power or acceleration, then all of a sudden it clears and all is well again. It will do this until either the engine has warmed up or the moisture?, if there is any anywhere has gone. It is worse when it has rained overnight. Very disconcerting when you try and pull away from a junction and you get nowhere generally being stuck in middle of road feeling like a right plank! If you pull away as gently as you can you can just about get away with it. Please help me as i love my 8v and she puts a smile on my face everytime i drive her but doing my head in at the mo.

Sounds very much to me like moisture inside the dizzy cap. On an 8v this can be a problem, once your car is warm it drys it out and is fine. In addition it gets worse after rain as the leads are very susceptable where they meet the dizzy cap and they will arc out.

You first problem sounds more likely to be an intermittant fault with the AFM, take it off and check the tracks for wear.

[8v Grunt!]

Thanks for the response. How do i check the AFM to make sure the tracks are ok? Will get new dizzy cap and rotor arm.

[ToddyGTi]

Thanks for the response. How do i check the AFM to make sure the tracks are ok? Will get new dizzy cap and rotor arm.

just prise the black piece of plastic off it, be careful and you'll have to glue it back on.

[8v Grunt!]

Don't want to seem thick but what am i looking for after i prize the cover off the AFM?

[ToddyGTi]

Don't want to seem thick but what am i looking for after i prize the cover off the AFM?

You'll see what I can only describe as watch internals. you'll see the tracks though and if they are worn it'll be obvious. If you're unsure, pop it off, grab a photo and post it up!