I've got a 1991 240 Automatic Wagon

Now, I know the redblock is tiny, and the car is huge, but this car seem unreasonably slow. Ive had other 240's that have been quite a lot faster, but never a different wagon. Does the extra 2-300 pounds really make that much of a difference.
whats happening is that it may loose speed going up hill, and unless I make the car kick down it won't accelerate past 80.

any help? maybe off on the timing belt

possibly clogged fuel filter

 

Also, even with primary highway mileage I always average 17 MPG

 

is this the same car that won't shift into overdrive (4th)?
17mpg is way too poor

 

Nope, good eye tho!
I have a 1991 wagon
My wife has a 1992 sedan with a transmission issue (which by the was is full of seafoam)

 

Maybe the hot air intake is stuck open?

 

I removed th hot air intake completely, pipe and all.
I live in Texas after all

I as more worried that it would get stuck and burn up my MAF

 

Are there any engine codes?

Given the mileage and poor performance my first thought was that it is in open loop or "limp home" mode. This means it wouldn't use the sensors to regulate fuel. You would have codes in this case.

Clogged cat is another potential problem yet I wouldn't think it would cripple your mileage

Last thought would be the timing belt slipped a tooth

 

Could it be a bad/faulty oxygen sensor causing the poor gas mileage? Bad readings might throw off the air:fuel ratio

 

No engine codes at all, even so I just reset the system by unplugging the battery for about 5 hours to establish a baseline

It really seems like a slipped tooth to me, because its hard to start cold or hot, but it runs pretty smooth...


@Cdubbs
As for the O2 sensor, I could try changing that, is there a way to test it?
I thought the CAT was clogged too however I took it off to find that it was gutted, completely empty...so definitely not clogged lol

 

I have no idea if you can test o2 sensors, but you do have another Volvo sitting around right? With a good o2 sensor?

 

Yeah but this thing is so rusted in I don't know if I can get it out with ought destroying it
looks like Ill just replace it looks like about $50

hmmmmmmmm

 

I'd see if you could test it before spending the 50 bucks. How much stuff would you have to remove to check the timing?

 

O2 sensor would throw a code. My guess lies with the timing belt. Not a too difficult job to check the timing marks. If the belt has unknown mileage on it I would just do a replacement since you will need to pull off all the covers and pulley.

 

Good point, no codes

The guy who had the car did all of his own repairs and wasn't very good. The belt is almost new according to his records, so that in my mind adds weight to it being the issue. Its cheap and easy to change, so ill tackle that and let you guys know how it goes.