To make a long story short....
1) Changed from rapidfire plugs to regular AC Delco plugs
2) Car was tuned specifically for the rapidfires 7 years ago and ran great!
3) With regular plugs car was misfiring at idle, timing was set at 0 TDC per under hood sticker. Idled perfect with no misfires, but car had nowhere near the power it used to have when the timing was advanced to 20 with the rapidfires. I took the car to a mechanic to look over. We decided to advance the timing 6 degrees. Had some of my power back, but car was bucking and shuddering when the gas pedal was released from 40 mph. down to 30 mph?? I thought that this surely was happening because of messing with the timing?? He said that it had something to do with the TCC switch or a pressure valve was going bad up inside the tranny pan?? I've never felt this bucking before....EVER..until today at the shop. I told him to put the timing back at 0 TDC and he adjusted the carb and idle. The bucking is gone and idles fine again, but now again has no power!! Does this sound like I have a pressure valve in the tranny going bad, and by advancing the timing to where it has good power is making the tranny problem more noticable?? And retarding the timing more is covering up the tranny problem to be less noticable?? Or is it because advancining the timing too far was creating the bucking and shuddering?? Thanks for any help!

 

5 years and only 39 posts..........what's up wit dat?

anyway, the part I put in red please delete from your original post. They are platinum plugs, big whoop dee doo

anyway, you are describing a carb adjustment and timing issue. Don't get caught up on spark plugs unless one is bad or has a cracked insulator. You may also need new wires cap and rotor

 

So basically you had the timing at 20 btdc and now you're running it at 6 btdc and wondering why it's a dog?

It's because timing has nothing to do with the brand of plugs. It has to do with what the engine wants at a specific RPM.

Find what your specific engine wants for initial, and then tune the distributor from there.

 

If your at 6 Tdc your timing is still off. You wanna start 4 degreese before tdc

 

Why?

 

I'm at 0* at 550 rpm currently. That is what the underhood sticker says.
torque is good-Never have much problems with the car. That's why I have very little posts. Wires, cap and rotor was replaced. Aaron_sk- The mechanic originally told me the timing was 20* advanced not btc, but car ran and idled very good that way for 7 years until 3 weeks ago when I decided to do a tune-up on it?? Does anyone know what the heck the bucking was when it was advanced to 6* (not retarded) and gas was let off between 40mph down to 30mph?? Currently idles perfect at 550 rpm and no weird bucking (like the TCC switch is going bad) at 0* TDC, but
doesn't have near the power it used to have.

 

I could be wrong on the 20* advanced, the mechanic acted like he was having a hard time reading the timing?? Everytime I asked him what the timing was on the 3 or 4 different times he set it and (test drove) he seemed like he was guessing?? He said the mark was hard to see. So who knows what the heck my timing was and is!!!

 

Time for a better mechanic.

You're not paying him to make guesses.

 

but we've missed you.

And, you can help with others who have questions

 

Is this still computer controlled? If not, firing at 0 degrees is the last thing you want.

 

It is computer controlled. Unless I unhook the 4-wire plug comming off the distibutor.

 

Ooops!! Put these pics in the wrong section. Sorry.