A friend in need...

**DirtDog** · 11-06-2008, 12:52 AM

Ok, my brother has a 1997 Chevy K1500 Silverado with a 350 TBI engine and auto trans. When driving along at highway speeds, the engine sputters and basicly runs like crap. If you floor it, it straightens out somewhat, bit it still sputters just a bit. The SES light also comes on and flashes steday for a few seconds, then goes out. it repeats this constantly. He already has installed new plugs and wires, and his air filter and fuel filter are good. What could be causing this? I'm thinking maybe the throttle position sensor or maybe an oxegen sensor. Any input on this would be greatly appreciated.

Thanks
Jack.

**dwill3015** · 11-06-2008, 12:57 AM

Could be a plugged catalytic converter.

**DirtDog** · 11-06-2008, 01:03 AM

Yeah, that could be a possibilty. I had not thought of that one. Thanks.

But would a plugged cat make the SES light come on and flash like that???

Jack.

**bry2500** · 11-06-2008, 05:26 AM

It can. did it on my 96 Monte carlo. Take the truck for a good rip up the highway and right after some decent speeds pullover and check the cat. I will be unusually hot and have a bad smell.Sometimes like rotten eggs. These are tell tale signs.

**GaryL** · 11-06-2008, 10:31 AM

Check the codes in the computer, it's trying to tell you something.

**DirtDog** · 11-06-2008, 10:54 AM

Originally Posted by GaryL

Check the codes in the computer, it's trying to tell you something.

Thanks, I would do that but I don't have a scan tool.

Thanks for all the help so far. I'll tell him to check out the cat.

Jack.

**MrShorty** · 11-06-2008, 12:15 PM

Originally Posted by DirtDog

Thanks, I would do that but I don't have a scan tool.

I expect I'll get some negative karma by saying this, but, IMO, if you are going to DIY diagnosis on these vehicles, you've got to figure out how you are going to get access to a scan tool. I don't have one is just an excuse. Sometimes parts stores like Autozone will pull codes for free in hopes of selling parts. I've seen a few shops willing to pull codes for free in hopes of selling diagnostic/repair services. A bottom of the line OBD-2 code reader can be purchased for $US 50-100, a bottom of the line scanner like I've got goes for $US 150-200, and on up from there, depending on how much functionality you purchase. "Guessing" at what might be causing the SES light to come on and flash is not a diagnostic procedure.

[off soapbox] That said, a flashing SES light like that means that the problem the PCM is seeing is one that it believes can lead to significant/expensive engine damage if not taken care of soon. O2 sensor/TPS/Cat codes usually don't fall into this category. Most of the time when people have reported a flashing SES, it seems to be a misfire code. Whatever the problem is, the best first step is to figure some way to get a code reader on it and find out what the computer has to report.