1998 sunfire 2.4 engine knock

my girlfreind has a 98 2.4 with 95,000 miles on it she was driving on the interstate the other day and ran over a tire recap from a truck a few miles after the the engine started to knock (might not have anything to do with the knock but wanted to tell the whole story) i checked the oil and it was a quart down the oil filter has no damage. i filled the oil and started the car there is a slight tap at idle but a knock at higher rpms. it sounds like something in the top end of the motor but i really cant tell. i am a automotive and diesel mechainc but have not messed with this type of motor at all. any help will help. i have read about some kind of timing chain tensioner and guides. thanks

The tensioner for the timing chain does break from time to time on these cars and make a knocking noise but the way you describe the incident I would check to see if the exhaust pipe was bent. Sometimes when these things get bent they will produce a knock in the engine. The other item to check is the motor mounts as you may have broken one. The oil issue would have been my first guess but you already took care of that problem.

thanks i am gonna have the car towed to my place so i can check it out better. i hate to have her go buy another car if this 1 is gonna be an easy fix. like i said i am a mechainc just dont know alot about these motors and know that some of them can get tricky. i think i will pick up a manual tomorrow and look it over

is it like valve clapping noises? im having issues with valve noise on mine.....it happens at higher rpm wen you kick the throttle.

i dont think its a valve its more of knock at higher rpms about 2500-3000 i could not tell right where it was comming from but it was not a consistant knock thats why i thought it might have been the chain hitting the case. i cant hear it at all when its at idle but i hear it when the car first starts and then when i bring it up to 2500-3000 rpm then i really hear it bad when i let off the throttle i did not wanna keep reving it up so i turned it off and will check better when i get it towned to my place.. i seen a parts veiw of the timing set up and there are alot of parts that can go bad in there most are cheap plastic.

FOLLOW UP
i finally got the motor apart first checking the timing chain and all the componets they where all ok and the car was in tim. so i took the intake cam cover off removing the cam,lifters and checking the valve springs everything looks good.. are the lifters solid lifters or hydrolyic . how can i test them??? i did not here a knock in the lower end so i am pretty sure its a lifter but they are 17$ each and dont wanna replace all 8 on the 1 side if there are a way of testing them. i removed the intake cam because this is where the noise was the loudest holding a screw driver to the top of the cover and my ear this is the only side i heard the noise on. i was sure i was gonna find somthing but i did not find anything at all... also the timing chain tenstioner when its reset how do u get it to pop back out to put pressure on the chain shoe ? the book really does not explain that. i reset it but i did not see a way to get it to pop back out... thanks for the help

yea..happens around 3000+rpm all the way to redline for me. wow, i might check it out soon too, just to see if the noise on my engine is in the same location. I do not yet know how to do the tensioner, but maybe i'll find out.

well i put the engine all back together i think its a rod knock the tenstioner is pretty easy to do but all that work and she is still knocking.... are u driving yours knocking ???

Sorry I read your previous post first and didn't realize you had gotten it running again. These 2.4's are a pain in the back side aren't they. As far as the knock goes someone on the other thread indicated that these engines have a problem with the number 3 bearing being oil starved. I guess you could run with the knock but if you are like me it will probably drive you crazy until you get it fixed. I wish you luck and welcome to the Pontiac forum!

thanks for the info yaa these little motors are a real pain.. there is alot of nonsence there i guess thats what happends when gm tryes to make a 4 banger with power just as bad as them trying to make a diesel. dont get me wrong i am a GM man 100%... well i will be dancing around the forums maybe i can help others like u guys helped me thanks again