100 series 4.5 slight miss

[Willy Hilux]

Here's the story. Got Gas fitted just over a year ago. They fitted new spark plug leads. After about 9 - 10 months it started to get a miss every now and then. It does it both on petrol and gas, so this cuts them out. I think it's the leads but I thought they would have lasted longer than 10 months. Seems to do it more in the wet weather as well.

What do you guys think??

[RAY185]

When does the miss happen? At idle? Under load?

I'd pull a plug for a look first. If they look old/fouled just replace and see if it solves the problem. While you're at it, make sure the plugs that are there are the right type for use with LPG. If plugs are ok you can do a resistance test on each lead to find the culprit. Dud one will be a much higher ohm reading than the rest (usually anything over about 12ohms is a throw away lead unless it is a very long lead) or open circuit. Since it's only a slight miss you won't have any open circuit leads though.

If it's only at idle I'd be cleaning the throttle body and idle valve.

[Willy Hilux]

It's happening on the highway. Not really under load. Also happens around town at 60km/h.

[stilivn]

What do you mean by miss, is it back firing also or just not firing one cylinder. I would check spark plugs first as lpg has been known to wear them out quicker than usual. Also look for excessive oil on any of the plugs.

[Willy Hilux]

Ok, Will start with the plugs. Will try to get them out this weekend.

[4wheelinls1]

Rough idle and a slight miss is valve clearances generally. If it is intermittant then possibly as mentioned plugs, leads or even a coil.

Joel

[Willy Hilux]

Cheers. Intermittant was the word I was looking for. Some days it won't happen. Some it will. But I think it is worse in wet weather. It's not a backfire or like that, it's like it just skips a beat. like a slight jolt.

[302 cruiser]

howd ya go