GQ Patrol missfire.

[leatherland]

Hi, this is John.



I have a 1991 GQ Patrol with a 4.2 petrol engine,

with a Carby, and a Points and Condenser distributor.



For about 3 years now, I have been getting an intermitent misfire that I couldn't fix.

It would not stall, but would missfire for about 100 metres, and then was OK for another 60 or 70 kms.

and then more misfiring.



The first time that it happened, I couldn't isolate the problem,

so I replaced the Coil, the Points, the Condenser, and the Plugs.



After that it ran fine for about 1000km or more. and then started to misfire again.



This time I only had a set of points with me, so I replaced them,

and it didn't missfire for about another 800 or 900 kms.



About 200 kms. back, I replaced the points again, and it again fixed the missfire.



Although this is not a problem that will leave me stranded somewhere offroad,

I would appreciate any suggestions as to what is causing the missfire.



I have never had any brand of points that would only last for about 1000kms.

and I am wondering if anybody has had this happen to them?



Any advice would be appreciated.



Regards, John.

[threedogs]

Hi mate and welcome to the forum, can you jump over to the intros and tell us a bit about yourself and ride.
Just something the Forum asks of us all,
Have you fitted the extended rotor button, could even be an exhaust leak, is it dual fuel??

[Family4x4]

Possibly upgrade to electronic ignition.

[GQ TANK]

im currently having a similar issue again.

Try a pertronix, with a flame thower coil and extend rotar button.

I have found - loose carby, crapy wiring, suspect manifold inlet gasket, corroded leads, adjusted tappets, cracked exhaust manifold etc. - One thing fixed at a time

With the carby = try giving it a shake - any movement? as they are 3 screws in the bottom of the arby that come loose.

[Shaft10]

Hey my mrs car was doin similar I changed everything ended up bein leads the only thing I didn't change lol.

[wannabeturboed]

Mine is doing it . I replaced the carby twice
had the distributer out for an overhaul,
new 10.5mm leads
new coil ,
sparkplugs
multiple external fuel pumps
removed fuel tank for a good cleanout
and it still does it intermittently

so today I gutted the distributer and put the pertronix ignitor 2 and flamethrower coil in but havent driven it yet I have the timing set again and ready to go but I can't get the idle down might just run it as is and see how long till it does it again

unless someone knows what im forgetting to do
and it still does it intermittently

[kevin07]

I had a slight miss in mine under load or just on the power a bit I changed the o2 sensor yesterday and boom the power increase is quite significant the old o2 all the holes were almost completely closed up and it was giving a reading of running lean whilst using 21l per 100. I need a couple weeks to get the new fuel figures but that annoying miss is gone and theres power.

[GQ TANK]

Kevin07 - the carby tb42s don't use a 02 sensor, although im thinking about fitting a wide band 02 to monitor the oxygen level.

Wannabetter turbo - your idle issue is probably not related to the dizzy - as long as you have the advanced connected.

Idle issues usually are an indication that the carby needs a kit.