1993 Chevy Suburban Shudder

I have a 93 Suburban with 297940 miles. I am noticing a shudder at all speeds when I am neither giving it gas or coasting but right in between, feathering the gas if you will. When I am giving it gas it accelerates and runs smooth. Coasting is smooth also. No backfires. Could this be a timing chain? I maintain and work on the car myself. Any ideas? Thanks!

By the way…it has a 350 with the Throttle Body Injection and 3 speed AT with OD.

if it’s a shudder thats usealy a transmission problem when was the last time the fluid and filter changed.

I changed the fluid about 3000 miles ago. I added transmission extender also. I did not change the filter at this time. But, if the filter was clogged, it would not shift into drive right away especially at startup because the pump would not be pumping enough through. Shifts clean and crisp into gear. Even when I am idling at 5mph giving her minimal gas she begins to lope. Maybe I’ll try driving not using overdrive…

[b]It could be a timing chain.

To find out, remove the distrbutor cap. Now rotate the engine back and forth by hand at the crank bolt. If the crank can be rotated more than a couple of degrees in either direction before the rotor in the distributor
begins to move, the timing chain is worn. On engines without distributors, remove one of the valve covers, and observe the valve action while rotating the crank back and forth. Again, if the crank is rotated more than a few degrees before there’s any valve action, the timing chain is worn.


Tester The belt travels about an inch side to side when I move the crank before the distributor turns. I’d say thats a couple of degrees! Should I pull the distributor assmbly and look at the gears or would it definately be the timing chain. The sad part is that I replaced the water pump about 10k ago and it would have been easy to do the timing chain at that time. Oh well. Thanks for the help!