stutter at around 70 between 3-3.5k revs

[Simpson]

as above if i take my foot off the throttle then gradually put down power on the motorway the car stutters till i get it out of the flat spot i take it injectors and the usual culprits first like leads etc which i have replaced already. Any other ideas? i have tried a search by the way but no post shows exactly the same problem, si far, i have tried all sorts in fac ti am bewildered now as allthe parts i have tried are second hand. Thanks 

[Conker]

16v or 8v?

I've had this twice (on my 16v). First time it was the overrun cut-off valve. Unpluged it and everything was hunky dory, although it might be the ISV controller behind the dash which is at fault (apparently also does something to control the OCV).

Second time it was an arcing lead/loose spark plug.

Also check your timing.

[rubjonny]

run it at night and spray a fine mist of water over the leads & coil, see if you can spot any arcing.  THe over-run cutoff is completly controlled by the isv control unit

[Simpson]

8 valve sorry

[rubjonny]

ideally with k-jet you need to get the pressure tested once you have ruled out spark & compression problems, then you can see whats up.  have you checked the metering head moves throughout its travel smothly and is clean?  Also has the idle, co and timing been checked?

[Simpson]

sorry its digipants, yeah idle is spot on as is timing and co, 

[rubjonny]

dunno where i got the idea it a k-jet! id say check the vac hoses and the throttle switches!

[Simpson]

robably cos t'ther lad was on about valvers! thanks as you might remember from my private messages i still have the lag from idle too maybe its related. I have changed everything, bloody thing, 

[Conker]

T'was I who started the K-Jet conversation.

Orginal post didn't say what engine it was. Muppet.

(I jest!     )

[spacerat]

i have the exact same problem on my 8v digi at the same speeds your saying(in 5th gear i presume), changed plugs,rotar arm, dizzy and fuel filter which didnt solve it, my isv definetly needs replacing/fixing as it fluctuates at idle, BUT i think the problem is to do with the second larger butterfly in the throttle body opening and the fuel/air mixture being wrong. im not a mechanic so i may be wrong but thats my opinion. and i will be watching this thread for any help too.

i also have that problem in 4th gear at certain rpm, not sure what rpm of the top of my head tho.

Kev