No pickup

Have a 1998 Volvo S-70 GLT… Amoung other things this is the biggest issue…The car huffs and struggles to go…

It started out missing when pushed into passing gear and has progressed to the point of being unable to reach 60 mile per hour going up a grade… I have to keep the car under 60mph and the transmission shifts find in E. Mode… Any pressure on the gas pedal will cause the car to buck… I was told that I could have a vacuum hose leak … The someone mentioned that this could be a C. Converter issue… Would like to know where to start…

How many miles are on this car?

How has the vehicle been maintained? I would start with maintenance items, like the air filter, spark plugs, and possibly, the spark plug wires. If you replace these items and you don’t see an improvement, you might need to find yourself a good Volvo mechanic. They are sometimes not easy to find, and they are usually expensive, but Volvos have many problems that are unique to Volvos, and it might not be something as simple as a vacuum leak. I hope it is, though, for your sake.

I have owned this Volvo since new… and it is maintained according to schedule…
Even the cabin filter is new… Every thing you mentioned is up to date… This car is used a lot for highway driving and that is where I first notice the problem…I will put in passing gear a lot… this car has great acceleration above 60 mph… The first time is started was on such an occasion… but other than that it ran fine… but as I mentioned it is getting worse… Turbo unit checks out fine… Guess my question is what are the signs of vacuum problems? Doesn’t seem to be a Gas/Air mix as the car runs fine when not pushed… UNIQUE to Volvo is an understatement… but I love this car…

A typical vacuum leak would be most likely to show itself at idle - producing an uneven/surge and fall.

Problems under load - pulling hills/higher speeds are typically ignition or fuel related. Poor spark, clogged fuel filter, weak/failing fuel pump.

It could also be a cat issue - or general exhaust, if the exhaust is restricted in some way.

Is the check engine light on?

Would a Cat. problem show it self at all speeds…? I have had the fuel filter replaced and the lines flushed … Fuel Pump failure would that be progressive?

At idle it is fine… and up to say 40mph then any pressure to accelerate unless done very slowly causes the bucking… The engine and Transmission were replaced at 140k … rebuilt Yes the check engine light is on… As it stays on a lot and putting it on machine usually does not show anything thing I sometimes think it is a false reading… I just had the main pully replaced along with the belt tenson unit… It was the abrupt change that had me concerned

Have the codes read and post them here. Many auto parts chains will read them for free. Post the exact codes: format - P0123