the intermitant kangaroo car

[paultownsend]

this is really annoying me now. in 5th accelarating circa 75mph'ish the car judders and wont pull. if i let off and gently put my foot down, its all ok and will pull strong. this weekend was the first time its happened this year, but i need to get it sorted before i soon hit the track.

the car-

91 pb 2.0 agg with bvh
fully serviced (plugs, leads, cap, arm, filters(+fuel) fluids with
set up as per rj guide +2' advance adjusted on rr
always ran on vpower

any ideas chaps?

[rubjonny]

what coil are you running it on?

[paultownsend]

the original coil to the car. bosch?

[rubjonny]

ah all mk2 managment & pb head?
have a look at the vac hoses from the throttle body to the fpr, maybe put a drop or 2 of machine oil down the vac nipple this has been known to fix a sticky one.  Also make sure the wot switch on top of the throttle body clicks, and check it electrically.  Quick & easy test for this, hold the throttle open just enouhg for the idle switch to release, revs up to 1.5kish.  Press the wot switch on top, and the revs should drop, then increase again when you release it

[paultownsend]

yep pb head and management.
wot switch operation all good. il try the fpr later.
its strange it doesnt do it in ant other gear. ie high revs in 4th. if its fuel supply related?

[rubjonny]

yeah bit of a strange one, might be worth chucking another afm on there if you have one to hand, see if it any better.  possibly its starting to run lean and the knock sensor is backing off the timing, that extra advance that was dialed in might have something to do with it, or it could be picking up a false signal.  Mine used to run a bit odd sometimes, never got to the bottom of it. then a week after i swapped it for a 16v I had a theory that the horrible rattly alternator mounted right next to the knock sensor could have had something to do with it, but I never could proove it as engine was already sold by then