2001 grand prix engine problem

[larry33kc]

My wife was driving it and it was cutting out, and sputtering, and would hardly run then there was a loud boom. The muffler had completely split down the seam and busted wide open, so I thought that the problem was the muffler had plugged up, since it ran similar when the cat converter plugged up.
So I cut the muffler off and went for a drive with no change cutting out and sputtering. It idles great, I can rev it and it is smooth till you hit 4000 rpm and it acts like it is on a limiter. But it runs fine if I power brake it, I can get it to 2750 and it is smooth under that load.
I put a code reader on it and there are no codes or issues. I changed the fuel filter with no change. I unplugged the MAF with no change.

I am stumped and I need to get it fixed, it is to be the down payment for my new car or I am going to have to pay the payment. I am thinking it is electronic but not sure and don't know what to do.

Oh ya this is a 3.8

 

[GNTIM]

check fuel pressure

 

[charlief1]

If it's a 3100/3400 it has 2 "cam sensors" on it. One goes to the rear (firewall side) of the block and if the intake gasket's been replaced the wiring's been screwed with. It's a 2 wire plug and I'll bet it's partially melted and is getting crossed causing the backfire ect issue.

 

[larry33kc]

Hvaent had to mess with anything lime that but I will definitely check it

 

[larry33kc]

Ok checked fuel pressure and it went to 50#s and stayed there. It never dropped or moved when it started to cut out. I didn't see any wires around the exhaust manifolds that could be burnt.
This is the 3100 v6 also. I am at a loss

 

[larry33kc]

Ok found it. It's a bad MAF. Thanks for the help.

 

[larry33kc]

Well im back. I put a MAF on it and it ran great for 2,3,4 days. I put it on CL to sell it and a guy came to look at it he and his son test drove it, and came back to buy it. We did the deed and off they went. Well I get a phone call about an hour later and it's doing the same thing. I asked him to unplug the MAF to see if that helps and no change.
I would really like to figure this out.

 

[charlief1]

You'll nee to get under the car to find the second cam sensor. It's a total pain to say the least but the wire's coming from the coil area and runs done to the second sensor. Hope that helps you out.

 

[larry33kc]

Ok if the guy calls me back I will tell or have him bring it back.

Just a quick question though. If it is a cam sensor wire wouldn't it keep it from running at all. And why would it be intermitane. Not questioning your knowledge just trying to understand what's going on.

 

[charlief1]

Wire may be moving around and if it's touching in a small section it may be ever so slightly kissing and then moving to let it run. It agrivated me for days trying to find the issue.

 

[garyk1970]

Check the crank sensor....