Can't figure it out...

[custom442]

I never had that happen before in a car so maybe? Transmission is the weak part of my car. Its a 307 with 275 hp and a 200M.

Where'd the 275 hp come from? Is this a stock 307?

try the simple stuff first - tune/timing/change fluids, keep marking things off the list and some problems may get better then let us know. It's hard to pinpoint something that you can't put your hands on... but I bet some of the problem has to do with the trans or converter

 

[robwkamm]

nos 150 shot probably burned the valves getting 275 hp. LOL

 

[megaladon6]

it sounds like a plugged exhaust (it can be more than the cat) or it's running lean.

 

[Riggs]

It doesn't have cats and it is a free flowing exhaust with headers. The engine has been rebuilt with heads, cam, and a lot of other stuff.

 

[dan2286]

It doesn't have cats and it is a free flowing exhaust with headers. The engine has been rebuilt with heads, cam, and a lot of other stuff.

Did it run fine after you installed the rebuilt engine?

 

[custom442]

It doesn't have cats and it is a free flowing exhaust with headers. The engine has been rebuilt with heads, cam, and a lot of other stuff.

I'm still curious as to where you got this number? What heads/cam? I can't see a valve job, more radical cam, and free flow exhaust adding over 100 hp to a stock 307. I'd have a hard time believing a nice port job would grant you those kinds of numbers.

If this number is what you say it is, then you need to junk the th200 and buy a new transmission because there's no way it couldn't be shot with that much power in front of it. God knows what the torque rating is if your hp number is actually 275. That'd be a converter/trans. problem for sure.

Get your engine tuned first though before moving on, there's no way to pinpoint symptoms with a hard running engine.

 

[Riggs]

I bought the engine from a guy who had the engine rebuilt and loaded with performance parts. The guy sold me the 307 because he wanted a 454 in his 442. The engine ran fine for a while but after like 3 weeks of driving it, it developed this Popping problem.

 

[SLICK79WGN]

pull your valve covers and look at the rockers while it is running I had one that did the same thing and it had a flat lobe on the cam

 

[custom442]

ya, popping/tapping is likely something in the valvetrain... your mechanic should be able to tell where it's coming from pretty easily, if not it might be time for a new mechanic. He'll at least tell you if the popping is an exhaust leak, rocker/valvetrain knock, or something else. It's not a rod knock as I assume you're getting decent oil pressure if you've been driving it

 

[kingcolbert83]

I know this has been said but I would check the ignition. As far as wires. We a old box chevy at school that acted like it didnt want to accelerate properly. Checked timing and everything. We finally figured it out when my friend got shocked by an arch.

One of the wire had a hole in it and it was making a popping noise. It would arch bad when he stepped on it and cause a misfire. Not saying his popping is the problem because his seems loud but if he is having a misfire somehow or somewhere this could come into play.