If I can move the crank pulley about 1/8 in+ back and forth, does that mean the chain is stretched? Truck has 88,000 miles now. I pulled hard on the belt from below and was able to move the damper/ crank pulley about 2inches counter clockwise looking from the front. I don't know if that's normal either?

 

That doesn't sound normal. I've never known a crank pulley to move like that.

 

Doesn't sound abnormal to me - you can sometimes turn the motor by hand via the crank pulley with some decent effort. Not a good test for the timing chain, however, with that mileage and age, I'd be checking the plenum gasket (if it hasn't already been done) and plan on a timing chain and gear set replacement if you plan on keeping the truck awhile.

 

My mistake, I read it wrong. I was thinking he could move the pulley in the housing and not rotating it. My mistake. I agree with atomic. Did a timing chain on mine and it runs way better. I did mine a 85000, and had quite a bit of stretch in it.

 

You're just turning the engine over. You SHOULD be able to do that.

 

Yes I plan on keeping along time. Have all the parts assembled for the plenum repair. Burning a quart 1600 miles, then another 1/2 quart next 600 miles. Also seems to be running lean. Plugs are clean and white after 8,000 miles. Slight miss and annoying vibration at idle only. So I was thinking what else mechanically could be causing those symptoms. Had the front crank seal replaced last November, was spewing oil all over bottom of the truck. Had fuel sync checked along with other sensors and couldn't find anything wrong. Feels like something out of balance though. Adding a double roller chain/ gear set to the list too.

 

When you pull your balancer to change the timing chain and gears, check the balancer closely to ensure the rubber hasn't deteriorated, especially since you had a badly leaking front cover seal. If the rubber has deteriorated badly, the balancer will need to be rebuilt or replaced, as this can cause balance issues if its spinning on the hub.

 

I wish it was the HB, but it appears to be in quite good shape. And the slight miss stumble while at idle only, is quite temperature dependent. Was driving me nuts late last summer into the fall. When temps dropped it was barely noticeable, it loved subzero days. This week is the first time we have hit 40 degrees and it's driving me nuts again. I am hoping it's the plenum leak that's causing that issue, extra air entering from the crank case, and it just opens up more when it's warmer out. We'll see!