Sumfin wrong...electrical possibly

[DANNY8]

I drop my bro to work every morning about 30 mins out of town (he lost his license). I use his car coz then it's his fuel I use and not mine. This morning on the way back into Pirie, I was sittin on about 100-110km/h in overdrive and everything started shuddering. I put it back a cog into 3rd and it seemed fine, then when the revs dropped a bit more it started shuddering again. Up a cog up into overdrive and it was still doing it, so back to 3rd again and tried accelerating. It was still shuddering but eventually came good after about 3 seconds of slight acceleration. Put it up a gear into overdrive and sat on 110-115 all the way back. I pulled over at the nearest servo (I had no phone so I would of been stuck if sumfin happened out on the road haha) and had a look under the bonnet....everything seemed ok, balancer looked good, gave it a few revs and it seemed fine. Looked under the car coz I thought maybe sumfin was wrong with the tailshaft or sumfin, but that looked ok too.

When I got back into Pirie the car was shuddering a bit again and it was misfiring heaps bad. Got back to my bro's house and parked the car, had another look under the bonnet and nothing seemed visually wrong. I put the revs up a fraction and the misfire stopped and it ran smooth again. Let go of the cable and it started misfiring again. So I turned it off. Then I locked it up and knocked on the door to wake up his g/f .....I told her not to drive it coz it was mis firing heaps bad and I wouldn't want her and bubs to get stuck out on the highway, and to just call me when my bro needs a lift back into town and I'll take one of our cars.

I know it could be various things, but just wondering if anyone could think of wat it could possibly be. Oh and it's a 91 VN 3.8 with about 370,000k's on it.

I'm not a VN person so I wouldn't know where to start looking haha :P

Cheers,
Danny

[Not_An_Abba_Fan]

Plugs would be my first guess. If it got better under load then it wouldn't be leads.
Did it smell a bit fuelly under the bonnet? Fuel pressure regulator split diaphragm can do that too.

[friedchicken]

Plugs would be my first guess.

agreed

my vn did that a couple years back, and it was plugs. i couldnt understand how a bad plug could make it feel like the gearbox was about to fall out

[DANNY8]

I've got a feeling my bro gave it a full service about 2 months ago, including plugs. When I go out to pick him up soon I'll let him know (he doesn't know about the problem yet haha) and yeah when we get back we'll take a look.

Thx for the help!

[WhiteLightning]

i once had the same problem and it turned out to be a boot on a lead had let go and wasnt makin full contact...took it to dad n he pushed em all n fiddles and it worked...thought i was imaginig things...5 mins down road started doin it agin...replaced leads n plugs...the lead fell apart...mite explain why it wasnt doin it after u checked em...cos u wouldnt no doubt fiddled with them a bit...and maybe the vibration in the engine changing O/D to 3 was enough to make or break contact each time...

[samuels]

I drop my bro to work every morning about 30 mins out of town (he lost his license). I use his car coz then it's his fuel I use and not mine. This morning on the way back into Pirie, I was sittin on about 100-110km/h in overdrive and everything started shuddering. I put it back a cog into 3rd and it seemed fine, then when the revs dropped a bit more it started shuddering again. Up a cog up into overdrive and it was still doing it, so back to 3rd again and tried accelerating. It was still shuddering but eventually came good after about 3 seconds of slight acceleration. Put it up a gear into overdrive and sat on 110-115 all the way back. I pulled over at the nearest servo (I had no phone so I would of been stuck if sumfin happened out on the road haha) and had a look under the bonnet....everything seemed ok, balancer looked good, gave it a few revs and it seemed fine. Looked under the car coz I thought maybe sumfin was wrong with the tailshaft or sumfin, but that looked ok too.

When I got back into Pirie the car was shuddering a bit again and it was misfiring heaps bad. Got back to my bro's house and parked the car, had another look under the bonnet and nothing seemed visually wrong. I put the revs up a fraction and the misfire stopped and it ran smooth again. Let go of the cable and it started misfiring again. So I turned it off. Then I locked it up and knocked on the door to wake up his g/f .....I told her not to drive it coz it was mis firing heaps bad and I wouldn't want her and bubs to get stuck out on the highway, and to just call me when my bro needs a lift back into town and I'll take one of our cars.

I know it could be various things, but just wondering if anyone could think of wat it could possibly be. Oh and it's a 91 VN 3.8 with about 370,000k's on it.

I'm not a VN person so I wouldn't know where to start looking haha :P

Cheers,
Danny

yep... check out plugs first,as suggested,if all turn out good,test CAS and coil pack.

[DANNY8]

Thx everyone for ur help.

I picked up my bro and brought him back, and we started to suss it out a bit more. He doesn't play with cars much, so I rekon it did him good to play with it. His girlfriend kept saying to take it to a mechanic coz we don't know wat we're doing haha. I said to her "ya gotta learn somehow".

But yeah, to start with we checked the leads to make sure they were on properly. They're only new as are the plugs. I took the leads off at the coil pack one by one and the 2 on the top one didn't make any difference at all to the motor when I took them off. They weren't sparking or nuthin...so I took the next one off which was below and it shocked me a few times so I guess that one was good.

We went down to Repco and got a new coil pack (it's not a 3 piece one, just a 1 piece), which costed about $65. Come home and chucked it on. Started it and it ran smooth as. Took it for a spin down the road and as soon as I put my foot down it started mis-firing again. So we figured the last thing it could be would be the module thing underneath coz there's nothing really b4 it. So back down to Repco and $135 later we had a new one. Come home, chucked it on with the new coil pack and it started ok....took it for a spin and everything seems ok. Gave it some stick and it never missed a beat. So it seems it was the module thing, but gonna keep the new coil pack on anyways, and just keep the other one for a spare.

My bro also said it sometimes kept stalling when it was idling at the lights and stuff.....but it seems to have fixed that to. So I guess it was the module thing that was causing that problem as well.

Anyways I'm glad we got it fixed, and wats better is we did it ourselves and it only cost $200, but if we took my bro's girlfriends advice it would of cost heaps more to take it to the mechanic, coz he would of charged extra.