lcguy1

My wife's suburban, 1997 5.7L, 1500, 215K miles, bogs down and almost stalls when put in gear. It seems to run fine, revs good, and idles good. As soon as you put it in gear and touch the gas, it bogs down and tries to stall. Actually it stalls most of the time now. Died on the side of the road last week and would not start. I replace dthe fuel filter first and it did not help. Over the weekend, I replaced the fuel pump with the Delphi OEM pump. Ran great for about 5 minutes and then stalls badly. I will try replacing the fuel filter again to make sure no junk was knocked loose during the fuel pump install, but I am not too confident. It seems funny that it runs OK when not under a load, but dies when put in gear. Anyone have any ideas? Thanks.

in2pro

Welcome to the forum..
Might try cleaning or replacing the IAC or Idle Air Control, as well as check out the TPS Throttle position sensor....
A few bottles of Techron in the fuel tank and if you see an improvement the injectors may need servicing....

73shark

I know you just replaced the fuel pump but you might want to check the fuel pressure. Gauge costs about $40-$50.

lcguy1

I hesitate to purchase a tool I will use only once, hopefully. I will check with a few friends to see if they have one I can borrow. One has a pressure gauge that goes in line, but I would have to cut the line and then replace it. Guess that is doable though. I will probably get a new TPS, they are not too expensive, about $60, heck, after all the O2 sensors and stuff I have thrown at this, it isn't that much. Thanks for your quick replies.

in2pro

Please DO follow up on what does and didn't work as that is what makes the forum work

Might check Harbor Freight if you have one nearby as they have inexpensive gauges that will be perfect for occasional usage and will sell pretty quickly at a garage sale if you decide you don't need it anymore later on...

lcguy1

There is a Harbor Freight in Missoula, I need to run up there next week anyway, so I will check it out. Thanks again.

lcguy1

Car will not start at all now. I can hear the fuel pump running though. Replaced the TPS and the Idle air sensor valve. Still would not start. Replace the spark plugs, but no go. Maybe it's time to seek professional help on this.

73shark

Well if it's turning over, then you are either missing spark and/or fuel. You need to determine which it is or maybe it's both.

in2pro

check the spark on several different plugs, spark should be good and strong and easy to see under the hood....also if you have removed the wires make sure they are all back in the correct sequence... ensure the coil wire is in good shape and making good contact...

lcguy1

Seems to have good spark on the cylinders I checked. I think the fule pressure is low. I hope to get a pressure test kit from a friend tomorrow and will check it out. It goes on the schraeder valve near the throttle body. When I check for fuel there, I do get a spurt of fuel, but it seems at ~42psi, I should get a larger amount than I do. Hate to drop the tank again, but I guess I will have to check all is ok with the new pump. Maybe messed up the fittings or something. Don't think so, but maybe.