That's TBI. The 8th digit of your VIN should be Z.

Do you have an SES light on? Any codes?

No, discoloration will mean nothing on an oxygen sensor. The procedure is around here somewhere.

 

I've replaced cap, rotor, air filter, fuel filter and plugs (no wires). Ran injector cleaner and combustion chamber cleaner. Very sporadic/random issue. Happens at anytime. It will drive fine one second and then at a stop light it sounds like it gets no gas when you step on th pedal. You have to feather the gas ever so slightly to get it to go. If you press on the gas normally, it chokes and may die if I keep on pressing the gas. When it gets to that state, then it idles at 2k rpms. There are no codes. I did replace the ecm very recently because I totally died on me. I'm thinking maybe a stretched timing chain? It does have just over 200k miles on it.

 

No holes

 

A stretched timing chain should not cause a spuratic issue.

 

Hi, 1983 s10, same problem, did you come up with anything? Had this truck 20 years and never this trouble before. @#$%^^^^help!

 

a good way to check the timing chain slop is to get number one cylinder on the top of the compression stroke on top dead center and pull of the distributor cap and see if the rotor is pointing at cylinder 1 plug wire but other than that my pcv valve on my 89 4.3 tbi actually made my truck hard to start and lose power from time to time.