[alanmcg]

Old thread I know.. but my 2 pence after googling across it.

I've had the bunny hopping, engine light and loss of power symptoms with the 1.4 petrol (1998 version). These are nasty but once traced shouldn't be expensive to resolve, just don't let them carry on or else they can ruin your catalytic converter. First thing to do is to make sure that the car is fully serviced, new filters & new spark plugs. Not expensive and should be done yearly. The 1.4s had a few different ECUs, IIRC Haynes mentions two key variants with differences in injection management, sensors, etc.

Get a Haynes Manual - this will give you a rough idea of how to remove things and what you're looking at. Get an error code reader (£40 or less for a basic one), this will spot any codes which show up and could very quickly identify the issue. The problem is that codes won't always show up, or stay stored, it is only if a sensor is totally screwed and the control unit turns over to its backup settings (with the accompanying loss of power & engine light & sometimes cutting out) that you'll get the codes stored. You'll also loss em if the car loses power (disconnected battery, surge during a jump start, etc). Nasty fueling problem causes:

- The Lambda or O2 sensor, a sensitive little bugger that sits in the exhaust manifold on the front of the engine, dodgy fuel tends to bugger this up. About £50 off eBay, apparently they can sometimes be cleaned, but a new one is probably wise. Shouldn't be a problem to fit.

- Idle control valve or stepper motor, £30 off eBay, common problem, results in lumpy idling, stalling, etc. Easy to fit, plastic part that screws onto the throttle body.

- (inlet) Manifold air pressure (MAP) sensor, primary issue with my car, another simple plastic part that screws onto the throttle body. Again about £30 on eBay.

Don't mess with the idle speed, you'll just confuse matters and waste fuel that way. Consider adjusting the throttle cable/making sure it isn't stopping the stepper motor from kicking in properly at idle.