Sputtering, loss of power when hot

hammer489 · #1 (**permalink**) 03-26-07, 11:19 PM

So my 92 deville 4.9 has had this problem before. I thought it was bad gas. I ran the gas as low as I could go, filled it back up and didn't have any problems. This was at the end of last summer. Now the same problem has resurfaced since it's warmed up. I will drive fine for 30 minutes, then at 25%+ throttle it will buck and sputter, and at 50%+ throttle it will flat out act like it's gonna die. It sorta sucks since it's hard to get out of other peoples way in traffic. If you shut it off and restart it will run great for the first 30 seconds then start again. I've also noticed what sounds like pinging when it's hot (before it started doing this). Any thoughts?

HUF · #2 (**permalink**) 03-26-07, 11:27 PM

Press Warmer and OFF simultaneously for a few seconds until trouble codes show up on the driver info center. Write them down and report. Turn ignition off.

hammer489 · #3 (**permalink**) 03-26-07, 11:50 PM

888 .7.0

I'm pretty sure from past experience that means nothing.

hammer489 · #4 (**permalink**) 03-27-07, 08:44 AM

And the service eng soon light did not blink. I know it's either the fuel readout or the ses light blinking that shows the codes.

carnut · #5 (**permalink**) 03-27-07, 02:52 PM

You need to verify fuel pressure is at spec 1st then if it is, check for arcing plug wires or a cracked spark plug. Wires or plugs generally wont set a code like fuel pressure sometimes will. Check those 3 things then report back.

hammer489 · #6 (**permalink**) 03-27-07, 04:39 PM

I will definitely check fuel pressure. I have read on this forum problems with the fuel tank baffles. What boggles me is the fact that it only happens when it's warm. I drove all winter with no issues, then wham! I can't believe I keep getting bad tanks of gas but you never know. The reason I don't think it's ignition related is I pulled plugs, changed wires, cap and rotor, pulled the module and had it tested, the last time I had this problem.

HUF · #7 (**permalink**) 03-27-07, 05:10 PM

Could be a bad ECM as well. It must be under glove box. You can try tapping on it when the car is actng up to see if it makes any difference. All the computers are very close to the heater core. It may be okay in the winter but in the summer can make difference.

thu · #8 (**permalink**) 03-27-07, 06:11 PM

This issue has been addressed several times on this board. You might try doing a search. Try using the terms "gas tank".

A thread has opened up on the other board: http://caddyinfo.ipbhost.com/index.p...pic=13185&st=0

hammer489 · #9 (**permalink**) 03-29-07, 09:44 PM

So I think I isolated the problem. Today the same old story. Sputtering and choking over 25% throttle. I left it idling outside my house while I went to get my fuel pressure gauge. The moment I attempted to hook it to the line and a little fuel came out the car stalled. I hooked it up totally and restarted it. 40psi. I hit the relief and could shoot fuel out of the tube while the car still ran. I rode around the block with the gauge still hooked up. As soon as it started choking again I pulled over to look at the gauge. The pressure was bouncing around between 25 and 40 very erratically. As soon as I hit the relief button it stalled. As soon as I started it back up the pressure went back to 40psi and I could literally squirt fuel from the relief with the car running. My question now is it the tank design, the sock, the fuel pump, or even the regulator? From what I've read on the link supplied, it looks that the tank goes bad from the baffles? What I don't understand is why a junk yard tank would be any better than the one I have?