i had the same problem on my 99, here's what i did.

1. thought it was the cat, replaced the cat-back.......still not fixed

2. changed the fuel filter........ still not fixed

3. changed the fuel pump assembly..........better but still not right under a load............still not fixed

4. changed fuel regulator............still not fixed

5. pressure tested fuel system......52-53 lbs.....called GM garage, they said it needed at least 58 lbs to run properly......replaced fuel pump again..............still not fixed.................

6. took it to GM garage they changed the harness( since the aftermarket ones required the stock one to be spliced) and put an OEM/GM fuel pump in it..........problem solved


btw......bill for GM garage........$801.00

 

I think I figured it out! I disconnected the connection between the cat and the muffler and took it for a drive. It was kinda loud, but it ran so much better! I am thinking the problem is definitely a blocked muffler. I was so tempted not to reconnect them and just drive around like that.

So, does anyone have any advice for where and what kind of muffler to buy? It doesn't look that hard at all to replace. I'm sure I can do it no problem. The only thing I will need help with is welding the tailpipe onto the muffler. But as far as taking the old one off and hanging the new one, I'm positive that I can do that. My neighbor knows how to weld and has the equipment, so I might just ask him to help me out when I get to that point.

I'm thinking about putting a performance muffler in it instead of a stock/regular one. Any thoughts, suggestions? Would it be better to buy online or just find someplace local? I don't have much experience with the exhaust system.

 

I've been looking online and according to Amazon, this one will fit, but then according to Dynomax it doesn't. Huh?

http://www.amazon.com/Dynomax-17748-...tive&carId=002

 

Ug...well, I got the muffler replaced. It's better, but there is still something wrong when I try to accelerate to hard. I think I'm going to have to bring it to the shop now.

 

Well, the shop finally started it's Saturday hours and I found the time to bring it in. They replaced the fuel filter and cleaned the MAF (which I had already done) and now it runs like a champ!

I think I still have an exhaust issue though. It sounds like there is a leak near the manifold. I'll take care of that soon. But in any case, it is now fixed. Thanks all for the help!

 

I'm having some of the same problems. every thing is fine for the first 10 miles then it starts. it don't want to accelerate passed 2500rpms and if I try the tranny slips and stuff. But I can pull over and clear the computer( no check engine light) and every thing is fine for a few miles. It's like the computer is seeing something and making ajustments till some thing is out of range. I had a code scanner on it and the timing and all the sensors looks OK.

 

Well, that didn't last as long as I had hoped...

Just recently it's started up it's issues again. Very similar to my previous posts, but not exactly the same. It's only happening in first gear now. It just started out of the blue too. I was driving it and it was running great. Then I stopped at a light, and when I went to accelerate, blah...it was bogged down again.

It would rev a little high in first and I can feel is shifting harder into second. But not like an extreme jolt shift like before.

And then today, I leave to go to work and not only is it still doing the no power in first thing, when it shifted to second, I think it slipped. The engine revved high before it "caught".

I just had the fuel pump/filter replaced about a month ago. Could that have something to do with it? Maybe a bad pump? But since it's only happening in first, I would doubt it.

Again, any help would be appreciated!

 

Are you popping any codes other than the one? I have a feeling (thanks to this forum) that it maybe a ground located at the last cross-bracing(drivers side) above the gas tank (pain in the ***).

i haven't been able to get to it as we've been having snow/ice storms here on LI. But i will let you know what happens.

I do know how ever that the EGR, fuel, shift solenoids, and some other none essential crap (are grounded there, don't know why but the are) that a carbuerated car never had, needed or wanted!!!!!! Not sure if i do either.

The codes i am getting are intermittent, p0101, p300, p404,p410, some random ones here and there,and last but not least p1626 (vtd alert in run position).

Thanks/Hope this helps,
Brian

 

O_o Wha?

 

True. I could probably go over to Advance Auto and have them scan it. Before when they scanned it they only got the o2 sensor code. But maybe something different will come up this time.