ChevyGirl1991

I have a '91 Silverado, that runs great most of the time, but sometimes will stall. its a 5.7 350 automatic 4x4 but sometimes after ive ran it for a little while and it starts to warm up, when I slow down or come to a stop, it will idle really low and rough and then stall. If anyone has any ideas what might be causing this please let me know! Ive heard everything from the torque convertor going out to a bad EGR valve...but im not sure. Thanks!

RacerX

Why not suspect the most likely causes? The throttle position sensor or the idle speed control solenoid?

in2pro

Might check for a vacuum leak, check your vacuum lines for cracks or splits...

ChevyGirl1991

Ok guys thanks for the tips!

hunterbs

Hey ChevyGirl,

Have the same problem on a 2000 Silverado. Just want to compare notes... Runs like a champ for a solid 20-30 minutes until good and warm. Then in stop and go traffic or when when slowing down, rpm decrease and stall. Sometimes it starts right back up, sometimes it acts like its flooded. Occasionally I can smell gas when it stalls.

Check Engine Light on? Mine throws a code on the EVAP system indicating a problem with vent canister, solenoid, or purge. Still working it this weekend, just wondering if you had a similar problem.

2wd-K5

hunterbs, your problem may be diferent than hers, your engines and electronics that run them are completely diferent, u may want to fine a thread on evap codes, chevy girl, when was the last time you replaced the cap,rotor and wires? sounds dumb, but this is the most common reason i have seen to make a truck run rough, as most dont worry about those things

also, there will be 1 vaccum line going from the throttle body to a small box on the firewall, this tells the computer what the vaccum is running at and lets it make decisions, if this is broken or disconnected it will do exactly what you describe with your truck

ChevyGirl1991

Hunterbs,

Yeah they sound like they are doing similar things. Like you said, when I first drive it, it will run fine, after it warms up is usually when I start to have the problems, sometimes if I shift it into neutral when stopping, I can rev the engine some and keep it from stalling, but sometimes regardless of what I do it will idle low, rough, and stall anyways. When it does stall the check engine light comes on, but other than that it does not come on. When I first got my truck back in January of last year, I noticed it would sometimes stall in reverse (especially when backing out of the driveway), but since then it just seems like it has gotten worse as to how often it will stall.

ChevyGirl1991

2wd-k5,

To be honest I dont know a whole lot about the mechanics of the truck, I like to learn dont get me wrong, but im not familiar with all of the basics of the engine, trans, etc... I do know that we (my friends, along with a little bit of my help) replaced the spark plugs and wires about 6 months ago, also has a new fuel pump and fuel filter, and has had some other ods and ends done to it, but other than that im not sure.

hunterbs

2wd, wasn't paying attention to the year. Your right, my problem ended up being evap vent solenoid. The older trucks should be more straight forward without all the new electronics,