Pete C 0 Posted April 18, 2007 (edited) A mate has just finished rebuilding the engine on his 1988 1.9 GTI. It has an XU10 head with the 1.9 cam, a lightened and balanced bottom end and a lightened flywheel, also an adjustable FPR. Everything else is standard bar an induction kit (which hardly counts) However, he's getting really bad jerkiness at low speeds, and even at higher speeds when descending hills on the overrun, for example. It's not the normal jerkiness, he and I have owned no less than 7 205/309s between us over the years so we know what that's like! It's similar to the normal type of thing, just much worse. So far we have tried: Adjusting TPS Advancing ignition timing Different AFM All to no avail. I'm not saying it isn't one of the above things, but we have tried Any suggestions? Edited April 18, 2007 by Pete C Share this post Link to post Share on other sites
GLPoomobile 958 Posted April 18, 2007 This may not be relevant as yours is a modified engine, but I have the same on my XU5 after swapping the head. In my circumstances I suspect the most likely cause is the cam timing possibly being out by a tooth. It was the first time I'd done a job like this and really struggled fitting the timing belt so reckon it's the most likely answer. Share this post Link to post Share on other sites
welshpug 1,657 Posted April 19, 2007 dump that FSE thing for a start, see what its like then. Share this post Link to post Share on other sites
DrSarty 90 1 Cars Posted April 19, 2007 Just an idea: a leak somewhere allowing extra air in, perhaps just after the AFM. Split trunk, loose jube clip? I hope it's that simple dude; must be really annoying. Rich Share this post Link to post Share on other sites
Grim.Badger 15 Posted April 19, 2007 I'd agree with Dr S on this one, it's probably a big air leak. Check the usual suspects first like the bolt holes on the inlet manifold but air can get in anywhere, even the oil breather system and injectors can leak air. What colour are the plugs? Share this post Link to post Share on other sites
lagonda 42 Posted April 20, 2007 Jerkiness on mine happened when I unscrewed throttle stop screw to reduce high idle resulting from timing changes. This stopped TPS operating correctly. Now everything is now more or less correctly set, jerkiness has gone, so I'd check TPS for correct setting & operation. Share this post Link to post Share on other sites
