Hey guys im new to the site and from some of the threads i've read, people here really know what their stuff.The 25th of this month i will be starting school as and automotive techinician because i love everything from my 1994 honda accord to my cr125 dirt bike. I just love engines, but im having a problem with my car about a month ago i added a cold air intake and JDM N1 style exhaust on my car and it ran fine, but one day i checked my oil and it was pretty low so i had my girl pick me up some oil and she got me 5w20 rather than 5w30, so i did some research and sence its winter, here in CT i figured y not give it a try my car was fine and ran great, but about a week ago at a light my cars idle started to go up and down, my dad says this is because im not getting enough back pressure and its because of my exhaust and now he wants me to chop off my muffler and put something else on. I love the way my car sounds and drives with my new parts, and i paid for all of these things myself i dont have the money to just give up a brand new muffler, so please can anyone help me?


sorry for the super long post, im just really upset about this

 

You dad hates your muffler and wants you to get rid of it, that's why he said it's the muffler. Your idle problem is either a vacuum leak on the intake manifold, air bubbles in your cooling system, or a dirty idle air control valve. You should fix it yourself and then put a silencer or baffle in your muffler to make it quieter which will probably make your dad happy.

 

i do have the silencer in and he still hates it, and even more now that for the past 2 days he had to drive it to work cause his 745li radiator basically gave out, so hes waiting for it to come, but saturday im going to take it to a friends shop and flush my radiator, and change the intake manifold, and clean the idle air control valve

 

i've heard a lot about the idle air control valve causing the surging idle, there's something for it in the FAQ section

 

This doesn't sound good... I cant think of many reasons you would need to change the intake manifold. I would stick with the IACV or a vacuum leak.