Lack of power when warm
 

i have a 90 blazer 350 tbi. Recently replaced Rotor cap, wire, plugs. There is a signficant lose of power when engine reaches operating temp. Also may or may not be related there is, i dont want to say knocking but a similar sound coming from drive side head. Now i check all the pushrods and they are good. Just looking for some input.

Have you checked the codes? If not, check out Troublecodes.net for the method.

Just checked th codes only thing im getting is code 12, now on troublecodes.net there isnt a code 12 for the 89-90 5.7 vin 7 tbi obd. what to do now?

Code 12 just means that it is finished giving codes. If your check engine light is on, but you are not getting any codes out of it... That sucks.

The fact that it takes the vehicle warming up for a bit for the problem to occur means that there is likely a sensor problem that is affecting the performance once it enters closed loop operation.

If you drive until it starts acting up, then turn the truck off and restart it, does the problem go away for a bit?

It is possible that an O2 sensor has started to fail. The O2 sensors really are not used during open loop operation, but would definitely cause problems if it is not feeding the proper exhaust O2 content to the ECU once in closed loop operation.

My check engine light is not on.

The problems continues even if i shut off truck and start it back up.

It is possible the o2 senor is fouled i removed it for a couple days while making a new exhaust system.

Now as far as the Noise coming engine, its like a Ticking that continues thru all range of RPMs.