I have a 1990 accord dx 5 speed and it will start backfiring and sounds like a miss. But it don't do all the time that's the thing. Also every now and then the rpms will drop lower than 750rpm then go back to normal, but not die. I have replaced the vss done tune up, plugs wires, cap rotor cleaned all the egr system adjusted the valves the timing belt has been replaced all the grounds cleaned and still runs like crap! Im running out of ideas and I dont want to take to a shop and have to pay them money to tell me what is wrong. Also no check engine lights are on either.

 

Have to ask first, are you 100% sure the mechanical timing is correct ?

Did it start after doing a timing belt job ?

Check your compression. See if it checks out ok.

Any stored codes ? Or you just assuming cause the light not on there are no codes.

 

I dont think so. I didnt notice anything. the timing belt was put on about a year ago and this just started about 7 months ago but was not that bad. Now its worse I thought it was something to do with idle so i have tired everything with the idle part and also I did have my valves adjusted and thats when it really started to do it. im getting them readjusted this weda and also having a compression test done too. But it shakes too which i thought it might be the distributor which i got a new cap and rotor, plug wires, plugs (which are ngk) and a new o-ring for the distributor. and after that it got even worse now im not sure. Also there is no check engine light or stored codes.

 

Have you checked your IACV and FITV? Repair and cleaning procedure in the faq at the top of the page.

 

Yes I have checked them and I also followed the thread on here on how to clean them too. I'm not sure still. The valves are getting adjusted today and they are also going to check the compression and the timing for me too. I will post what was wrong tonight.