Hey guys sorry i havent been around fr a while been super busy with school and such. But i REALLY need some help with my bird. She is a 1987 Firebird Formula with the 305 Tpi. She starts fine and idles alright. What happens is when im driving it when i get to wround 3k rpms she will start to make a poping noise(coming from the driver side) then she will fall on her face and not "Pull" any more. It feels like something is holding her back. Rpms will raise but car just doesent pull as hard. I hooked up a scanner to her and the car is advancing fine and is running normally but when she idles she idles to lean but when you flooe her she idles to rich. I have a new computer new maf new egr valve new ecm(in the dist.). No-one can figure out what is wrong with my car. ANY help would be awsome. But plase not " well you problem is the 305" jokes. one i get this running good its going to be getting a heart transplant with a 383 T.P.I stroker! when i get the money. So PLEASE help me out. I am super close to selling her.!

If you are still running stock exaust. The catalitic (sp) converter might be stopped up . I had an 83 olds cutless do the same thing.

The cat is emptie. It was cloged and i thought that was the prob and emptied it and it ddnt fix it.

Put a vacumn guage on it and see if it fluctuates. The popping could very well be a broken valve spring? I can not remember if the 87 is a roller or flat tappet type camshaft in 87. Have you checked to make sure you do not have a lobe going away? Just a thought.
The vacumn guage will tell you alot. It should be steady, if it dances around like crazy you better pull the covers off.
Hope this helps.

Put a vacumn guage on it and see if it fluctuates. The popping could very well be a broken valve spring? I can not remember if the 87 is a roller or flat tappet type camshaft in 87. Have you checked to make sure you do not have a lobe going away? Just a thought.
The vacumn guage will tell you alot. It should be steady, if it dances around like crazy you better pull the covers off.
Hope this helps.
I have an aftermarket vacume gauge and it is very stady i floor it vcume goes away i let off it goes to about 15-18 and some times even 20 and it is really stady. Could it still be a busted valve spring?? Even if the vacume IS STILL STEADY.???

I have an aftermarket vacume gauge and it is very stady i floor it vcume goes away i let off it goes to about 15-18 and some times even 20 and it is really stady. Could it still be a busted valve spring?? Even if the vacume IS STILL STEADY.???

I kinda doubt it, unless they are just low on open pressure. Your vacumn is normal, at WOT the vacumn does drop off. The popping ( or is it backfiring ?) could possibly be a fuel delivery problem, have you checked the fuel pressure? The falling on its face could very well be a lean condition or Fuel.
Is it a TPI? If so it should probably have around 35 psi, and if you unhook the vacumn bypass to the fuel regulator it should be around 42-45psi if memory serves me correctly. Have you also changed the fuel filter recently? TPI,s are hard on fuel filters.

A buster valve spring wood cause a misfire and valve train noiese!.....I' tinking it's a clogged injector or low fuel pressure!:yes::thumbsup:

I kinda doubt it, unless they are just low on open pressure. Your vacumn is normal, at WOT the vacumn does drop off. The popping ( or is it backfiring ?) could possibly be a fuel delivery problem, have you checked the fuel pressure? The falling on its face could very well be a lean condition or Fuel.
Is it a TPI? If so it should probably have around 35 psi, and if you unhook the vacumn bypass to the fuel regulator it should be around 42-45psi if memory serves me correctly. Have you also changed the fuel filter recently? TPI,s are hard on fuel filters.

When i am at wot there is not vacume and there is a brand new fuel filter, Yes its the tpi nd when i hooked the scanner up to it when it was floored it was running Rich when it idles it was running too lean.Also that is what im trying to find out if it is a backfiring, or just a poping noise.

A buster valve spring wood cause a misfire and valve train noiese!.....I' tinking it's a clogged injector or low fuel pressure!:yes::thumbsup:
I will take off the valve covers and see if anything is loose or broken, Can you also tell me how much psi i am running on my car? It the 305 T.P.I. Cause i have a fuel pressure gauge but it only goes to 70 psi.

I will take off the valve covers and see if anything is loose or broken, Can you also tell me how much psi i am running on my car? It the 305 T.P.I. Cause i have a fuel pressure gauge but it only goes to 70 psi.

A 70psi guage is fine, but you need a special hose with a schrader valve adapter to fit on the fuel rail pressure checking point. Reread my above post for fuel pressure specs.