340 pulling at gear change (3rd)

Hi
I have just found this forum and I have to be honest it was a joy reading it cos it is already answered so many questions for me!!.

But I have a specific query and wondered if anyone can help. I am currently trying to get my trusty Volvo 340 (1.7GL 1990) back to optimum running condition after a 4 month battle with a faulty carb. I shall give you the history of the problem but try and be brief:

1. Initially car stalling on motorway. It would lose power and then stall. Only happened at speed. Got distrib cap, spark plugs and leads changed. Made the problem worse. Eventually got new second hand carb. Still as bad.

2. Put the car into volvo garage. They changed fuel filter and carb gasket and patched the car up so it would run but diagnosed a faulty carb and recommended a new one to solve problem.

3. So after saving up we managed to get new carb (from eurocarparts) bought and fitted. Great... the car idles better than it ever has (steady about 900) and seems to drive pretty well.

Now to the problem. Initally when we got the car back we only drove her locally ie not on the motorway where she had had the problems. Finally plucked up enough courage to take her on the motorway and she was juddering /pulling when you lifted your foot off the accelerator in 4th or 5th gear and speed. Since then with more local driving this has stopped but was then juddering slightly in the lower gears whilst driving. Now it has changed again to only pulling whilst changing into third gear and little when you are acclerating towards 4th. Sometimes by being very smooth with your cluth/accelerator transition she won't pull.

Does anyone have any clues what's going on?? We were wondering if it is the carb 'burning itself in'? Or something as simple as spark plugs or leads as our previous mechanic (who fitted the useless secondhand carb and was a bit useless) changed them and we wonder if he hasn't done it right?

Any help would be greatly appreciated. And also it was great to find a forum such as this online...many thanks to Steve from uk.rec.cars.maintenance for recommedning it!
DD

[srtames]

Hi, glad you found the site.
I have had a similar problem with a misfiring engine but if it runs alright round town and judders only on the motorway it could be your engine mount rubbers,gearbox mounting rubbers , rear axle crossmember mounting or possibly a sheared propshaft rubber (the prop has rubber sections to insulate vibration) . If you poke them you probably find oil from the back axle has perished one.
There is a register of non-franchise volvo specialists available if you join the club.


good luck, steve

Just to let folks know think we finally found the problem with the 340 pulling. According to our local garage it is carbon buildup on the valves(?) as it is an older car (G reg) with high mileage (145k). He used a substance called 'forte' (sp?) on the car and it is much much better but we can still feel a slight pull now and again. He said apart from removing the cylinder head there isn't much else they can do about it. Was glad however to be told this as another (less scrupulous) garage had diagnosed a slipping cluth and quoted us £200 for a new clutch. Only the fact they couldn't take it in for a week made us go to the second guy. Anyone got any ideas concerning this?? Do you reckon another treatment of 'forte' would do any good or is it an all or nothing thing?

Cheers DD

[pettaw]

try putting in a really good fuel in like Optimax and then go for a good blast round to ungum the valves.

I would also check the valve clearances and if in any doubt change the olugs, leads and dizzy cap.