Hi!

I was going up a long hill on the highway today, and my 740 Turbo Intercooler won't even go over 120 KPH up the hill. I put it into 2nd gear to try to speed up a bit (A cheap Honda Prelude was gaining on me!) I looked at the temp guage and it was under 1/2, and it was jittering back and forth. As soon as it went back into 3rd gear, the temp guage went back up (not all the way to 1/2) and was steady!

The car sucks on the highway but seems to accelerate pretty fast on normal roads. If I put the pedal to the metal, it really has no power, (especially on the highway) the turbo goes near red, but no extra power is gained.

What is the deal with my car!?

If most of your acceleration problems occur at highway speed, it could be a partially clogged fuel filter. Fuel demand is highest when at speed and when you accelerate, the additional fuel demand may not be met with a dirty filter. In my experience, symptoms of a partially clogged filter first show up at highway speeds and spreads to all driving conditions as the filter gets worse (which may take a while). I can't explain the jumping temp needle with this theory, but depending on mileage and maintenance history you should consider replacing the fuel filter.

or rather your cat....

Or as suggested your turbo may not be boosting per spec....

"The car sucks on the highway but seems to accelerate pretty fast on normal roads."

Please define.

Paul-

Whenever I complain about performance problems at the Volvo dealer, a mechanic comes and drives it on city roads only. He floors it and says "well, doesn't seem to be anything wrong" On the highway, over 100 KPH, the car is gutless, and especially up hill, I can push more and more on the accelerator, but all that happens is the turbo needle goes closer to the red- nothing else.-whoopdey doo. maybe a 5 kmph increase.

When I turn a corner on a normal street and try to accelerate, the car drones and really doesn't do anything unless I manually put it into 1st gear (Auto Tranny). As well, the cars idle is a bit rough while sitting. -I'm getting really frustrated with them and I wondering if I'm expecting too much from the car. Sometimes after I start it up, it is extremly smooth and a joy to drive, but that's very rare.

They said the turbo was putting out more power than it's really supposed to be set to do. The AMM was recently replaced, as well as the Turbo Downpipe hose. But no performance difference was noted.

Could a lose hose cause the thermostat to fluctuate like that at high RPM? I tried it again tonight on normal roads, and it seemed to go down as RPM increased and then started wiggling.

Thanks for your help! Sorry for the long msg, but I thought I's give details in case it gives anyone a hint as to what could be wrong.

I'm not 100% sure the temp gauge is related, but a restricted exhaust system would behave as you describe and cause the engine to run hot at higher RPM.

I say, just have it tested...any mech. should be able to test for exhaust back pressure.

Then also do all the normal tune up stuff, clean throttle body, update turbo and vacuum hoses, etc. What I'm saying: check the simple stuff first and make the car stock. If this doesn't work then start thinking rocket science.

Check the 700/900 FAQ via the link below. Lots of good info there.

Sounds like a leak in turbo system.

Check you turbo hoses for splits or holes. And look for a vaccumn leak.

Check the underside of the 3inch connector hoses.They tend to get soft from oil laying in them. And check the nipple area where the pcv hose enters the intake hose to the turbo.