whenever i'm in 4th or 5th gear, just cruising at a steady pace over 3000 rpm. Sometimes it feels like the car jerks, and goes back to normal. It's a noticable jerk, but a somewhat smooth transition.

also, in first gear coming from a complete stop, a noise coming from under the hood would make a scraping noise. It's only when i'm on the clutch, as soon as i release the clutch, the noise goes away. It'll make the same noise when trying to start in second gear. It doesn't make the noise in reverse.

My cat converter is also making a lot of rattling.

 

the noise from the cat is most likely the heat shield on it broken. I had the same problem and just cut that thing off. Ive done it on a few cars and havent had any problems. If that isnt it check the heat sheilf the rides along the underside of the car, make sure its bolted in properly and not hitting against anything. And lastly check all the hangers on the exhaust, make sure they are all there and in good shape.

The car jerking at steady cruise. There are many causes for that. Is the car warmed up at the time this occurs ? Also do you have a check engine light ? Does it feel like it misses or hesitates ?

 

removed the heatshield. it's still making noises. hangers are intack and i retightened every bolt, they were torqued down before..so it's on there good.

No check engine light, car IS warmed up. It doesn't feel like it misses a gear. it's a 5sp manual.

 

When he says "misses" like that he means a cylinder misfire, like it fails to spark correctly.

I have the same problem, mine is due to a long standing wiring situation though. Tell me this, does it only do it at a very certain point on the throttle? Mine won't do it if I'm even slightly decelerating or accelerating at all, but if I'm on a flat road, constant rpm, it will miss like hell. Its really weird.

 

I have no clue what a cylinder misfire is. Can you explain more?

 

When the mixture in the cylinder doesn't explode it is called a misfire.

 

one thing that i know may happen at constant rpm, bucking can be cause by a bad tps. The tps is a potentimeter and if a section of the windings is worn (generally the throttle postion you are normally at most of the time) it may cause that. However it would not cause an actual misfire just a hesitation.

 

good call dude

 

check plugs wires etc, change fuel filter, make sure air filter is clean 2.

 

its most likely not the tps but if u know how to use a meter. Hook it up on the signal wire KOEO and do a sweep of the throttle. You should see a steady increase in voltage starting at around .5 volts (closed) to around 4.5-4.8 WOT. This is not a very likely cause however so dont get your hopes up.