Issues with hesitation on 98 S70 GLT Turbo

buffsstuff1 · Post by **buffsstuff1** » 30 Jun 2010, 11:30

I have had a performance nightmare for awhile now. I have started calling my 98 S70 GLT Christine it has gotten so bad. I hope that someone maybe able to point me in the right direction. I bought my volvo for my daughter and grandchild so they would be safe. My daughter couldn't handle the gas mileage (she drove a Honda 5 speed) so her car became my curse. I have taken it to the dealership and repaired/replaced everything they said was wrong with it. So I assumed when I went to sell it that it would perform like it should. Drives fine for me, but everyone who gets in it and drives it it stumbles, hesitates, and just can't get out of its own way. I do not floor the gas EVER. I noticed the last one I rode with did. I have been on here for days looking to see what else it could be-the car wasn't driven much by my daughter and even less by me. I have replaced the plugs, changed the oil and had some engine degunker put in it( helped a bit), had the injectors cleaned. I am at a loss and at wits end. When the check engine light came on-it was a o2 sensor-replaced it. I have looked on here for days for what else it could be, could you please help me so I can send Christine to a new home. I do not want to sell a POS that is why I continue to attempt to fix things. Any help would be greatly appreciated:)

Post by **jblackburn** » 30 Jun 2010, 12:20

I betcha it's a mass airflow sensor.

Just after the airbox, there is a plug. Unplug that, shut the hood, and take it for a test drive. You'll have a check engine light, but if it acts better, you just need to get a new sensor.

That could also be why the gas mileage was so bad - I too came from a Honda that got 40 mpg highway, but out on the highway, I have seen up to 32 in the Volvo...not bad for a car with almost twice and a half the power of my old Honda

buffsstuff1 · Post by **buffsstuff1** » 30 Jun 2010, 12:56

Thanks. I tried that and it acted worse-popping and chugging and finally dying. I looked at the plug wires and one has a crack so i am heading to get replacements. I will keep all posted.

Thanks for your help,
Owner of Christine(my 1998 S70 GLT)

buffsstuff1 · Post by **buffsstuff1** » 01 Jul 2010, 17:28

Ok, so today I replaced the spark plug wires-slightly better, the rotor button/distributor cap-no difference, and oil change. Now it is showing an o2 sensor code... Runs slightly better to begin with but when you put the pedal down, she can't get out of her own way.... Working on the o2 sensor.

buffsstuff1 · Post by **buffsstuff1** » 01 Jul 2010, 19:58

So after a loooong time under the car, the o2 is replaced. Only problem is it runs worse now than what it did before. Could I have not got it plugged back in enough or something? I=stumped.

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This is what the o2 sensor looked like when it was pulled out.

Post by **jblackburn** » 01 Jul 2010, 20:07

At this point, I would try to get my hands on an OBD reader that shows real-time data. Take a look at the values for the MAF sensor and O2 sensors. Unless you used a non-Bosch O2 sensor, something is definitely wrong. Have you tried testing fuel pressure?

buffsstuff1 · Post by **buffsstuff1** » 04 Jul 2010, 03:21

I crawled back up under the car and the O2 sensor wasn't pushed in all the way. It does better than what it had been, but still not like it should be. Would a vacuum leak from the evap purge line cause the hesitation/stumbling? Or would that cause other issues? What would cause it to run rich? Any advice/comments would be greatly appreciated:)