98 cobra pops when idles and car dies when stopping/low rpms. HELP PLEASE!!!

mhungaski · 08-15-2009, 07:53 PM

I have a 98 cobra and when my car idles my exhaust makes a popping noise. it sound kinda lopey and it idles low but just like a random popping pattern if that makes sense? it idles up and down between 500 and 1000 rpms and the other night while i was driving and coming to a stop i pushed the clutch while braking and the car just died. i was able to start it back up immediatley but i kept giving it gas while i was stopped because it was sounding like i twas going to die again. also when im slowing down to park or if im in a drive thru fast food restaurant in line the rpms will drop down to maybe 400 or so and i will continually give it gas because i think its about to die. ive just changed the spark plugs and cleaned the idle air control valve and today i went to oreilly to check the battery and alternator and they said both were bad then took it to autozone and they said both were good. the battery is fairly new roughly 10-12 months old but i have also installed H.I.D headlights and foglights a total of four ballasts, a tachometer, aftermarket radio (no amp), and LED dash lights so i dont know if that stuff could be causing the problem maybe need a more powerful battery i dont know. please help me!

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a_penquin · 08-15-2009, 08:02 PM

Are you throwing any codes? If so let us know what they are and we can help you from there. The alternator and battery should not be causing you car to run like this, possibly a crank sensor from what you've said so far.

mhungaski · 08-15-2009, 09:21 PM

check engine light is on but when i took the battery to get tested i reset the computer so tomorrow when it comes back on i'll get the codes and post them please chack back and help me i need all the help i can get before i have to take it to a shop

SVTeeshirt · 08-16-2009, 02:33 AM

i think its your Mass air flow sensor.

i'd try to clean yours its not hard just don't **** up the sensor.

if it feels a little better but still having problems replace the M.A.F.

if its still having slight problems check for a vacum leak or replace the I.A.C

actually check for a vacum leak before getting a MAF lol clean yours and look for a LEAK.

smoke is a good way if you have any device that smokes your engine will suck in the air at the leak.

mhungaski · 08-16-2009, 08:24 PM

im gonna be cleaning the MAF sensor later on i'll let you know how it goes the check engine hasnt came back on yet so i cant get it scanned but im sure it will here in a little while

devongarver · 08-17-2009, 03:33 PM

You know, I have the same "popping" every once in a while while the car is idling. I have now power loss, and the IAC is brand new, but the rpms do dip a little more than they should still every now and then, but never stalls. If it is idling, and i stand behind the car, i hear blub-blub-blub-blub-blub-blub-pop-blub-blub-blub..etc. I never could figure out what this was. all the COPs and Plugs are new, I cleaned the MAF last year, but maybe it needs it again?? Any other ideas? Its never thrown a CEL. So I never thought it to be a major issue.

mhungaski · 08-17-2009, 10:13 PM

I cleaned my MAF yesterday and cleaned the IAC again and still nothing im probably gonna try replacing the fuel filter tomorrow. Whenever i put my hand and cover the exhaust it doesnt pop near as much also it feels like when my hand is over it whenever it does make a pop that it almost feels like its sucking in a puff of air. I have no idea what it could be but the car hasnt stalled again but the rpms are still fluctuating between about 500-800 rpms and it drops everytime there is a pop noise. I'll try to make a video and post the link so y'all can have a better idea of what im talking about.

P.s. my check engine light still hasnt came back on yet

devongarver · 08-18-2009, 07:42 AM

Sh*t,...I wonder if its a small backfire we are getting, my exhaust is pretty open, save for the highflow cats,...I wonder if its running too rich at idle or something. Damn i wish i wasn't a tard when it came to this stuff..

mhungaski · 08-19-2009, 04:42 PM

I think it might be misfiring I just went to autozone today to get my check engine light checked and p0156 and p0161 came up and it means check bank 2 sensor 2 o2 sensor but i believe thos are the after cat sensors and i have MIL eliminators so they couldnt be throwing a code ti also says possible explanations are

xygen sensor defective, system running very rich or lean, engine misfire condition, fuel pressure very high or low-fuel pump or pressure regulator. im about to change my oil and put some lucas oil stabalizer and sea foam engine treatment in my oil, gas, and vaccum to see if it will help clear it up nd im changing my fuel filter hopefully tonight so ill let you know how it goes.

Smokin04 · 08-19-2009, 07:55 PM

It sounds like you have a vacuum leak man. They can be a pain in the dick to find, you just have to look...and then look again. 02 sensors do go bad and when they do it is a MUST that you replace them with Ford 02 sensors. Bosch or any other sensors just dont cut it.

Also, the wrong heat range of plugs would make a car run crappy like you're describing.

Edit: Also a leak big enough in the inlet tube post MAF would stall the car out