Hi everybody,Well i got a wierd problem,i bought this volvo 740 gl 1989,the car only had one owner befor me and it only has 146 000km's,its was in really good condition,i could do atleast 170km's with the car,and ever since i cleaned inside the hood,(the motor etc..) my check engine light appeared and the car would puff black smoke,went to the garage,they changed the idle valve,the ecu,the mass air flow nothing worked,till they changed the oxygen sensor,my car stopped puffing black smoke but the car wasnt so economic on fuel,with about 45 litres i do 250km's that not much,I also checked my spark plugs,and i changed my spark plug wiring,the car still smells gas,and it has no gas leaks,i have a poor acceleration,the car seems to have a hard time shifting,i cant go higher than 140km's Any help?Im really bumed out on what the problem could be

Thanks

Hi valade,

Sorry for the delay in getting to you. Your problem is a tough one and it seems that you have done a lot of the right things to help solve your problem. could it be remotely possible that your brakes are dragging? 740 are prone to this. This would cut down on milage, overwork your drivetrain and cause some of the things you mentioned. One test is while you are driving normally let off the gas and see how quickly it decelerates. Do this when the brakes are fairly cold.

A long shot but give it a try.

Don

740 gl means its a 4cyl non turbo..right?

the car has all of 110 or so hp

check up on the maintenance