poor gas mileage, no power uphill.

gondwana · Post by **gondwana** » 13 Aug 2012, 19:13

The car is a 98 v70 t5 with 185,000 miles. I have no check engine light on. No stored codes. I was thinking that is the CC is going out or plugged. I can't get passed 65-70 mph's on freeway. O2 sensor's are original never changed. What would be the best way to attack this? Looking for the least expensive way.

Thank you

Recently replaced

full tune up
oil change
fuel filter
air mass meter
air filter
pcv kit

Post by **Ozark Lee** » 13 Aug 2012, 19:27

If you suspect the catalytic converter let the car cool off and then bang on the converter with your hand. A bad converter will sound like it is full of gravel.

Normally you would get a check engine light with a bad converter with a range limit code on Bank 1 Sensor 2.

...Lee

Post by **jblackburn** » 13 Aug 2012, 19:38

Are you sure there are no air hoses loose?

Check ALL intercooler hoses - especially the one at the bottom of the intercooler. I've had one blow off slightly without throwing a code before, but it was dumping out most of the air before it reached the engine.

gondwana · Post by **gondwana** » 13 Aug 2012, 21:39

When replacing o2 sensors do i need to replace both front and rear?

madspeed50 · Post by **madspeed50** » 13 Aug 2012, 22:15

Do you have a boost gauge? What is the turbo doung? Is it working hard but not getting you anywhere? Or is it the problem?

Yep, sent from my rooted, rommed Galaxy Nexus....

madspeed50 · Post by **madspeed50** » 13 Aug 2012, 22:16

I had a MR 2 turbo that did this when the turbo took a dump

Yep, sent from my rooted, rommed Galaxy Nexus....

Post by **cn90** » 13 Aug 2012, 22:38

To diagnose a clogged catalytic converter, it is very easy.

With car in Park, ask some one to rev up and down the gas pedal while you stand at the tail pipe with a piece of paper right at the end of the tail pipe, the paper should "fly" when the rpm goes up, if not, the cat is clogged!

gondwana · Post by **gondwana** » 19 Aug 2012, 12:34

Ok replaced front 02 sensor but, both front and rear sensor's are very close to each other the CAT is original from factory.
Should i replace the second one also? I thought the rear sensor was after the CAT? There is some performance gain and better mileage.

madspeed50 · Post by **madspeed50** » 19 Aug 2012, 12:48

pull out the rear o2 sensor and clean the soot off it

Yep, sent from my rooted, rommed Galaxy Nexus....