I have a 98 Tahoe with 169,000 miles and a host of problems. This has been a real dependable truck until lately. About 35,000 miles ago, she really started burning oil. She now burns a quart every 500 miles. Some of this is leakage, but two cylinders, #3 and #5, seem to be the culprits. These two cylinders will trash a set of Bosch platinums in 20k miles. The plugs on the other six cylinders come out beautiful with textbook wear. #3 and #5 plugs come out heavily fouled with very excessive wear on the electrodes. The engine has also been making a clattering-type sound under acceleration. It's hard to explain, but to me it kind of sounds like a diesel engine clattering. She usually only did it under acceleration at speeds above 55, but is now doing it at speeds from 25 on up. This week, two new problems started. My truck idles high now, even when it's warmed up. She used to idle at around 600 or 700, now she rarely idles below 1100. I've also been noticing that she will occasionally miss at interstate speeds. It's not a minor miss either, it's a shudder for a full second. She isn't leaking or using coolant, and my gas mileage has stayed constant. I do appear to have a blown O2 sensor, but the mechanic I had read the code said he wasn't sure which 'bank' was not working, and that they were expensive, so we left it at that. I've recently relocated, and don't have a trusted mechanic yet. Is there anyone out there who's experienced similar problems, and did it result in a rebuild. And if I need a rebuild, anyone have any advice on replacing my 350?

Two words


Crate Motor


Do not bother with a rebuild or a "autozone engine" go with a GM Crate motor, look online. Summit.com. CAG.com Jegs.com

Just be ready to pay about 15-20 hours for R&R @ $65-$95 an hour

Kt



I would bet part of the problem is the lousy boush platnums, put in the GM ACDelcos.