Well this is my first post along with my first Volvo. I found a nice S90 with only 130xxx miles. The car looks to have been taken care of, at least I have a file folder full of receipts from buying a bulb to replacing a steering gear and all the oil changes.
This car has ran great until the other day I was cruising down the interstate at 78 MPH when all of a sudden the car acted like someone shut the fuel off. The check engine lamp came on and when I scanned it the code was P0172. Well I cleared the code, shut the car off, then restarted the car and it ran perfect. The major problem is when you go to accelerate the car stumbles and acts as if it is running out of gas. The more gas you give it the more it hesitates and stumbles.
So I went thru some of the All Data flow charts for codes P0172. I checked the voltage at the Mass Air Flow connector at terminals 2 and 4 and found that I was coming up with 7 volts which was way to much. I replace the Mass air Flow checked the voltage again at terminals 2 and 4 and got a .125 which is within specs, All data states between .1 and .15.
So after I installed the MAF this car ran perfect, no hesitations, had great power no CEL. After about 20 miles the hesitation came back, and I believe it is worst. I cant get a check engine light to come back on. From what I can tell the problem comes back after it gets a certain temp. Since the first time the problem showed up it looks as if the temp gauge is about 1 or 2 specs over the half way mark of the gauge, nowhere near the read marks, but a little past half way.
I have retested the MAF and it still test perfect. I am at a loss and don't really know where to go from here.
I can tell you one other thing. The first time this issue showed up, I did notice that when it first hesitated it did backfire thru the intake and I think it may have blew a line off of the PCV system. I have noticed the smell of burnt oil and also noticed that I have quit a bit of blow-by from the dipstick and the oil cap. The car never had this blow by before.


SO ANY HELP WOULD BE GREAT AS I REALLY NEED SOME HELP NOW


THANKS

 

I know that I am new to this forum, but I really need some help with this one.
I can say that the hesitation is not temp related. Yesterday while driving with a cold engine at first the car acted like nothing was wrong. It would take off great and go thru the higher RPMs with no issues. The all of a sudden it fell on its face.
As long as the gas pedal is only given slight pressure it never does it, but once you hit the majic spot it hesitates, cuts out, maybe a backfire thru the intake. The car has never shut off. Even if you give it more gas the worst off it gets. This issue has be banging my head against the wall, don't know if I should sell it or fix it. I have read a ton of great things about these Volvos, like almost being bulliet proof.
I will say that this car rides and drives BETTER than any of the Cadillac's or Mercedes's I have had. All of those cars were very ez for me to work on but this Volvo has me a little worried. This car has NO ROT OR RUST which I found to be the best thing along with the miles and it also has a PERFECT body, no dents, all orginal paint just needs a good wash and wax.
I have a few other small problems that I need to do:


1) Fix the A/C to blow out of the dash vents
2) redo the PCV system
3) Have the drivers side seat bottom repaired
4) Do a complete 140,000 mile service

 

could be one of a few things - Since you are planning to do a full servicing, start with plugs/cap/rotor/wire and perhaps the coil just to rule out spark as a problem. When you pulled out the MAF, how did the intake look? if oily you may need to clean the ICV and the throttle body as well. Could be fuel pressure - relay, fuel pump, fuel pressure regulator etc. Also inspect the vacuum lines for leaks (usually I'd expect a leak to throw a code) just to be sure. Does the behavior change with temperature ie cold engine vs warm, cold day vs warm day? (there's the engine coolant temp sensor, an intake air temp sensor etc to consider if you see changes day to day).

 

If you have no proof of the timing belt being done, get it done pronto!

 

I know this is a year old but this sounds like a plugged catalytic converter to me.