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Loss of Power

3K views 11 replies 6 participants last post by  FLUFFYBUNNY151 
#1 ·
Hello All,

I have a 2005 Astro with 185K, and having an issue with loss/lack of power when accelerating anywhere from 80km/hr to 100km/hr. Also notice it when towing a trailer or passing other vehicles. Any time the van is under load or calling for power she lets me down. SES light comes on and stays and after a few restarts, disappears. Error codes lead to the Mass Air Flow sensor which has been changed, but still getting the error with the capacity of the air flow. Plugs, wires, cap & rotor have been changed in the last 20k, new fuel filter in the last 5k, oil changes and air filter changes regularly.

Any help would be appreciated! Thanks :)
 
#4 ·
Basically you will want to remove the O2 sensor infront of the cat, and go for a drive. If you performance improves, your cat is going bad.

That's about all I can suggest. I am very green too.

Good Luck and keep us posted.

Jim
 
#5 ·
Don't remove the O2 sensor. That works, but you take the chance of ruining the sensor an it can get expensive fast.

What Jim's trying to tell ya is that you need to check to see if the Cat Converter is plugged. There's a couple of ways to tell, so let me give you some simple ways:
  • In the dark, after the engine's been run and is hot, lift the hood to see if the exhaust manifold is glowing dull red, or look under the van at the Cat Converter to see if it's glowing red (either one's an impressive sight).[/*]
  • Go under the van an pound on the converter with your fist. If you hear a lot of stuff rumbling around when you hit it, it's plugged/plugging.[/*]
  • Go to your local Mom and Pop muffler shop. They'll do a free back pressure test that will tell if the converter is plugged[/*]
None of these tests are really destructive and will tell you the same thing as removing the 02 sensor.

Another way of testing the converter is just take a punch and punch a small hole in the converter and drive around a while to see if the power is restored. Then if you find it is, replace the converter. If not, then put a screw in the hole you made... to plug it. I don't recommend this way... I like taking it to the muffler shop.
 
#6 ·
LEVE said:
Don't remove the O2 sensor. That works, but you take the chance of ruining the sensor an it can get expensive fast.

What Jim's trying to tell ya is that you need to check to see if the Cat Converter is plugged. There's a couple of ways to tell, so let me give you some simple ways:
  • In the dark, after the engine's been run and is hot, lift the hood to see if the exhaust manifold is glowing dull red, or look under the van at the Cat Converter to see if it's glowing red (either one's an impressive sight).[/*]
  • Go under the van an pound on the converter with your fist. If you hear a lot of stuff rumbling around when you hit it, it's plugged/plugging.[/*]
  • Go to your local Mom and Pop muffler shop. They'll do a free back pressure test that will tell if the converter is plugged[/*]
None of these tests are really destructive and will tell you the same thing as removing the 02 sensor.

Another way of testing the converter is just take a punch and punch a small hole in the converter and drive around a while to see if the power is restored. Then if you find it is, replace the converter. If not, then put a screw in the hole you made... to plug it. I don't recommend this way... I like taking it to the muffler shop.
Thanks Leve

I appreciate the assist.

Lord knows I could use one sometimes.

Thanks Again

Jim
 
#7 ·
Thanks for the suggestions, its appreciated. I think I'll take it to a muffler shop, get them to check it out. Would a computer not come up with an error for the cat converter when it displayed the mass air flow error? I don't know whether its related or not, but I also have a ticking sound and when I am accelerating, about 3-4 seconds before shifting to the next gear, there is a rattle, then it dissapears once its in the next gear. I've run a couple tanks of premium through her too, to help maybe clean out any fuel injector issues. If the cat converter was plugged/plugging up, would I not notice any loss of power at lower speeds or it running rough?
 
#10 ·
Jim & Leve, thank you for your help! I took the van to my local muffler shop and they did a heat test on the exhaust system. The second cat converter was not hot like it should be, and after removing it, found it to be completely plugged! I had both cat converters replaced and she's running beautifully now! Thank you!

Cheers,
Darryl
 
#11 ·
CdnAstro05 said:
Jim & Leve, thank you for your help! I took the van to my local muffler shop and they did a heat test on the exhaust system. The second cat converter was not hot like it should be, and after removing it, found it to be completely plugged! I had both cat converters replaced and she's running beautifully now! Thank you!

Cheers,
Darryl
Congrats and Kudos to you...

You Sir, Have kept another Van on the Road.

Jim
 
#12 ·
idle fine but the exhaust manafold glows red in minutes there is not cats on it and the exhaust is not blocked the dash light showed code 42 so I replaced the icm but that didn't work it back fires and u can only get in 2nd gear 20mph to the floor I'm at a loss iv tried plugs wires coils icm grounds and vacuum lines iv pulled the exhaust off and let's put it this way I could use the flame that's comes out as a cutting torch
 
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