pk222

hey guys, I have an 89 mustang gt and I'm just curious if somethings wrong. My car starts up different all the time. like sometimes it will start up great others it will kind of studder sound like crap until it starts but then sounds normal. recently its been revving up to about 1500 rpm on start up every time without me giving it any gas and then it does a really silent backfire or just a little pop that I dont know what its coming from.
Is this bad? I know it starting up differently means somethings not right, I recently cleaned the filaments on the mass air meter and I need to change my air filter, could the filter be doing anything? I'm also going to change my fuel filter, I dont know if its time to do this or not but I just figured might as well because I dont know when the last time it was changed was.
thanks in advance for any input

pk222

anyone?

WhiteWindsor

Have you messed with anything else like the distributor?

mjr46

try cleaning the IAC......and run a koeo/koer test and check for codes and make sure you don't have any vaccum leaks

pk222

sorry if i sound dumb but what is the IAC? still a noob I know but I've learned a lot from the site. and no I have not messed with the distributor at all. also I've checked over a few times for vaccume leaks and have not seen or heard any. recently I had a cap on the vaccume tree split but I replaced it.

Next time I'm by a place that can check the codes I will have it done.

I dont know if this will help solving the problem or if this is something completly different but sometimes when I shift the car reves up a little more when my foots completly off the gas( its a manual) like i usually shift around 2-2500 rpm and it reves to like almost 3 and stays there for maybe 3-4 seconds being the longest. could this be from the same problem or anything else?

thanks for your replys

pk222

anyone else help just a little more?

would a new mass airflow sensor possibly fix this? also the exhaust sensors( forgot the actual name but know what they look like and that they can cause major prolems if they go bad)

getafewlives

Whens the last time you did a tune up? ie plugs, cap, rotor, wires.

pk222

like either last month or the month before I did a tune up

pk222

also I havent been able to set my timing because my harmonic balencer is bent and the readings jump from 10-11 but I might try to bump it up to 13 degrees and see how it acts and if it goes bad Ill put it back down. do you guys think this could be a way of solving the problem? also I use regular 87 octane gas would it be ok to run my car at 13 degrees with it running on that octan or could this be the reason my cars acting wierd?

pk222

anyone?