I have a 1988 S-10 pickup with 358,000 miles with a developing problem. First of all, original owner, runs great but it has started to intermittently, for a few seconds or several seconds while hot or cold, run as if there are only 3 cylinders working,for exsample,pull a spark plug wire off and then reattach it. The dealer said they found the exhuast manifold has a leak,which it does (minor), spark plug wires, dist. cap & rotor, fuel filter and heater core all need to be replacedto improve drivability. Over$1,500.00 worth.AfterI asked what did the diagnostic computer find, they said"a false lean code". Well the heater core has nothing to do with thatas probably with all the other items.

Any Suggestions?

 

Lean code is from your cracked manifold. Valve overlap causes outside air to suck in crack confusing O2. Not bashing your vehicle but w/358k its had a good run. Dont invest that much money into it.

 

I would have to sat that after 385,000. miles you may want to invest the $1,500, into a 1989 or so with maybe 200,000. on it,[8D]