Misfire - 1.9 Gti

[TU_Later 0]

Basically I'm getting a horrible misfire/ backfire.. I timed it up with a timing light, and drove it.. Spot on for 10 minutes, and then it develops a horrid misfire which makes the car feel and sound like a TVR Cerbera Speed 12.

 

What baffles me is, it goes between misfiring and running SWEEEEET (For about 10 seconds occasionally).

 

AND, if i boot it.. It seems to sort of misfire up untill 4000RPM and then clear out! :S

 

 

Please help, This car's going to kill me soon.

 

 

Steve

[MrG 3]

are the coil/ign amp new?

[Weser 30]

Was it cold when you started and run it for 10mins?

 

As I had a problem with my coolant sensor in the block. Basically ran fine when it was cold but then as it warmed up it overfuelled and ran horribly!

 

You would be able to smell the overfuelling though! easy way to check also is to pull off the wire to this sensor. When the problem occurs.

[mikeygulley 19 1 Cars]

Was it cold when you started and run it for 10mins?

 

As I had a problem with my coolant sensor in the block. Basically ran fine when it was cold but then as it warmed up it overfuelled and ran horribly!

 

You would be able to smell the overfuelling though! easy way to check also is to pull off the wire to this sensor. When the problem occurs.

 

I had the same problem as this. Its worth checking it Steve.

[Grim.Badger 15]

It sounds like a problem with some wiring in the ignition/ecu system somewhere or possibly a duff component.

 

Double check for breaks in the wires, corrosion or lose connections on the ECU temp sensor and AFM first.

Ignition amp may be a culprit if it's dead as Mr G suggets, or you removed/disturbed it and the silicon gel isn't fresh.

 

IMO it won't be the belt, otherwise it would run badly all the time.

[TU_Later 0]

The culprate was a poorly charged battery.. Changed it for a new one and its spot on, So i think my alternator is slowly dying out!

 

But ive got different misfire at roughly 4000rpm, like a quick few splutters and its away again.. And i think its the Ignition AMP. Where can I buy one or how much are they? I dont even know what it is to be honest!