Loss of Power, Intermittent, Usually When Accelerating Hard

Loss of Power, Intermittent, Usually When Accelerating Hard

Postby gexamb [OP] » April 17th 2009, 2:17am

I have a 2003 Chevy Astro Cargo Van, 4.3L 6cyl RWD.

I have been having this problem for a month now. The problem is that the van loses power when accelerating hard, for example when trying to pass another car on the freeway, going uphill, and when driving on the streets as well. Sometimes it drives like normal, and then suddenly loses power when I accelerate hard. My mechanic has check numerous things on the car: Changed MAF from a salvaged van, fuel pressure good, cat seems fine it has no rattle no black smoke no backfire. there is a code that pops up for something wrong with the vacuum. the check engine and ses lights go on when problem occurs. and the problem occurs when the car is warmed up to operating temp, not when cold. What can cause this to occur?

o2 sensor? vacuum leak? fuel injectors? but i am thinking that if any of this is the problem, the engine would misfire, right? the engine does not misfire by the way.

I hope someone can help me with this. thanks to all.
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Re: Loss of Power, Intermittent, Usually When Accelerating Hard

Postby Matrixx » April 17th 2009, 4:30am

Hi gexamb

Welcome to the Forum

If you can post the code that lights up every time this happens, then I'm sure we can steer you in the direction you need to be in to find it. Most auto parts stores can scan the vehicle for you for codes for a small fee or even free sometimes. Thanks.:)
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Re: Loss of Power, Intermittent, Usually When Accelerating Hard

Postby gexamb [OP] » April 17th 2009, 8:11am

I got a b0101 MAF sensor fault but I think I figured out the problem already. I took it for a spin but I really pushed it this time. I pushed to the point where it lost power, i kept accelerating at full throttle, and then I heard that famous sound, the cat was rattling like a harley almost. so im gona get it replaced and see what happens next. btw the cat would offset the MAF sensor fault IMO.
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Re: Loss of Power, Intermittent, Usually When Accelerating Hard

Postby gexamb [OP] » April 17th 2009, 9:34pm

i did not know how exp cats are for this car. do u guys kno any other sources besides the dealer to get some cheap cats? i live in california every aftermarket cat i find is not legal in california. help me guys.
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Re: Loss of Power, Intermittent, Usually When Accelerating Hard

Postby Big_kid » April 18th 2009, 2:17am

Ouch!
Can you test it with a straight pipe first to be sure that's what it is?
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We have enough youth. How about a fountain of smart?
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Re: Loss of Power, Intermittent, Usually When Accelerating Hard

Postby Matrixx » April 19th 2009, 7:36am

Hi gexamb

Have you looked at the Magna Flow Cats?

Main Site:
http://www.magnaflow.com/

Cat Site:
http://www.car-sound.com/02product/02universalepa.asp

Hope something their helps.:)
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Re: Loss of Power, Intermittent, Usually When Accelerating Hard

Postby 'cudapaul » April 19th 2009, 4:40pm

Your catalytic converter may be under an extended warranty.
Since it is an emission component is is covered under a Federal warranty that goes to 8 years and 80,000 miles.
If your van is less than the 80K miles, go to the GM dealer and ask if can be replaced.
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Re: Loss of Power, Intermittent, Usually When Accelerating Hard

Postby gexamb [OP] » April 21st 2009, 2:31am

its passed it warranty, 92k mi. It got fixed tho. it was the cats in the end that was causing the problem. What the muffler guy did was cut off the small cat and welded on a straight pipe. He cut off the main bigger cat and replaced it with a magnaflow cat. its working pretty solid now. Problem vanished immediately. Thanks guys faor your help.
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Re: Loss of Power, Intermittent, Usually When Accelerating Hard

Postby Matrixx » April 21st 2009, 6:06am

Hi gexamb

I'm glad you got it sorted out.:)
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