Help! My Cobra is bucking and popping over 5000 RPM!

[93_Snake]

I took my car out this weekend, and I hammered it from a stoplight. I was running just fine until I got just a little over 5000 RPM. Then it started bucking and popping real bad. I have a new set of plugs, but have not put them in yet. Think that will fix it? It runs great up to 5K then it is really bad. Help!

 

[TcM-668]

Sounds like you might have a valve spring going bad, and allowing the valve(s) to float.

I would do plugs, a set of wires, rotor and distributor cap, and recheck the timing. Try replacing the fuel filter too. If you have a fuel pressure gauge, check the presssure too.

It could be spark scatter too. Hook up a timing light and rev it up to around 3500-4000 rpm and see if the timing jumps around on you. If so, then the bushings in the distributor could be going south. the other thing could be the ignition module on the distributor.

Beyond that, I dunno...

Good Luck...

Don...

00 R # 152
93 GT Conv
93 LX Coupe
92 Honda Accord EX Wagon
89 Isuzu I-Mark Hatch SunSport

 

[93_Snake]

I think I found the problem. After I changed my plugs tonight, I was around the back of the car listening to the exhaust while it was idling and found that one of my cats must be clogged. One side is putting out a lot of exhaust and the other is not putting out much at all. I know how to fix that real quick!

 

[hillie16]

(RedSnake busts out the straightened coat hanger.....)
LOL

 

[93_Snake]

LOL, I am thinking about that as a quick fix until I can get a new cat setup:burnout: