lots of lifter rattle when accelerating. If this blazer was from the 60's and 70's I would say that the timing is too advanced. also if I add fuel injector cleaner or sea foam to the fuel it does it less. the fuel at the pump is 87 octane.

So the question is here if the knock sensor has failed or not working properly would it throw a code.

the fuel pump is 3 month old and the cap & rotor and wires and plugs have been change (Delco parts / Delphi parts) air filter is new.

it just seems that the timing is to advanced.

Note: there are no codes in the ECU or nor is SES light on

 

The knock sensor definitely will set a DTC if problems are detected by the ECU.
Sounds like you've made a couple of reasonable observations based on symptoms; for example, boosting the apparent octane rating slows combustion (normally as pre-ignition).
Go after the obvious first - the first thing I would do (and have done successfully[sigh]) based on your recent service is to ensure that the individual spark plug wires are routed correctly from the distributor cap ports to their respective cylinders based on firing order. Also ensure that they are firmly connected to the spark plugs - a couple are real buggers to get at. I lift the front-end and remove the wheel to access a couple of them.
You might ensure that both the cap and rotor are properly seated and secure, too.
More-severe misfire will set a DTC; it may be such that plug wires are switched on two cylinders that fire succession.

 

I have re-checked that cap and rotor already. and yes the wires are a booger to get to.

the cap, rotor, wires, and plug were replace almost 3000 miles ago. along with the fuel pump & filter. the transmission was replaced about 14 month ago (note: the shift patterns are a little flaky. sometime if you get in a hurry the trans has a hard shift from 1st to 2nd but everything else is fine)

been thinking about getting a used PCM from the salvage yard and get my info and send it off to PCMs4less and get one that is tuning. just have not had the budget for it yet. my secondary air pump has bearing going out and it almost sound like a warble siren. and I have one lifter that pecking on number 3 cylinder.

some of my thoughts are

• the transmission might be lugging the motor (not for sure on that)
• the air pump shouldn't effect timing
• the ticking lifter (could causing part of the problem)
• the fuel source I using might lack quality of octane.
• cylinders and pistons and injector all should be clean. (1000 mile trip with seafoam added every other tank full.)
• the fuel pressure is good (test good)
• throttle body was disassembled and cleaned
• Idle air control was cleaned
• EGR was cleaned and new screen gasket installed
• Air filter was replaced
• all vacuum hoses replaced 3 or 4 months ago
• now no exhaust leaks
• converter are clear no blockage
• muffler is clear and no blockage
• no DTC code set.
• cooling not a issue new water pump and radiator and all new hoses, new idlers and belt tensionor and new belt.
• alternator run about 13.8 to 14.3 volts (during high temps 13.2)
• all connections on PCM tight and clean.
• MAF was cleaned 3000 miles ago all air connection check and tight.
• intake might be leaking a little water I added about quart in the last 2 weeks (might be air from heater core replacement)
• I have seafoamed the motor directly and in the fuel

this blazer was my wife's old vehicle it has 135,000 miles on it. oil was change regularly, but other maintenance was a little lack because it wouldn't sit still long enough for me to do scheduled maintenance to it. so I have been playing catch up and just about got all the bugs and maintenance done.



still to do list

• replace intake gaskets and replace lifters.
• bearing on AC compressor.
• replace PCM with a Tuned PCM.
• replace secondary air pump

not necessarily in this order.