3sfe Lurching

[picnicfan]

My Picnic (3SFE engine) is lurching when picking up from small throttle openings. Say you are trundling round a roundabout at 1500rpm then depress the throttle (even gently) to exit, the engine dies momentarily then lurches forward. Sometimes you get a bit of 'kangarooing' before it pulls away.

I've replaced spark plugs and leads (direct ignition, no distributor). No improvement.

It is OK when the engine is cold and also better at low air temperatures. These are times when the ECU is enriching the mixture so I'm guessing it may be running slightly lean. I've replaced both temparture sensors but still no improvement.

Any ideas? Could it be low pressure in the fuel rail? Is there an easy way to test?

Duncan

[BALIKBAYAN]

When was the fuel filter changed? To me it sounds like the engine doesn't get enough fuel when you "suddenly" tell the engine to use more fuel.

[Jamesbelfast]

Blocked fuel filters rarely clear themselves and are likely to give problems at times of high demand - that is when the engine is reving high. Even then a dirty filter is more likely to cause intermittent problems.

What many people tend to forget is that when the accelerator is depresssed the ignition timing must change. Assuming the ignition timing control is vacuum operated I suggest that aspect be checked out next.

95% of engine faults are down to electrical controls failing to operate correctly.:)

[bothwell_buyer]

The 3sfe was fitted in a number of other cars like the series 1 RAV4....so maybe there might be an answer in that forum...try a search?