88mustanglx

alright, here is the deal, i got an 88 mustang 5.0. For emissions i got rid of the fuel regulator that was put on it by the previous owner and put a stock one on and did some other exhaust crap to pass emissions. This was like a month ago. Today i go to start my car up and it keeps stalling or the RPM's keep dropping and its just a really rough idle. even after i rev it up a little bit. As long as i keep the engine Reved up to a little it wont stall. Then out of nowhere it will idle fine. The car always had a bad cold start or whatever you wanna call it since i first got it that was over a year ago. I will start it up and once in a while it will stall but just rev it up to about 2 and a half RPM's and its fine. Im not sure what is going on this time. But also I noticed the other day when i nailed it getting on the highway around 4-5 RPM's it almost felt like i put the car in neautral or just let go of the gas. Not a transmission problem i dnot think i think it might be a fuel problem. Also when reving the engine once in a while now i keep hearing a loud pop noise. Anyone idea what this is? Im hoping its just the fuel regulator but im not sure. ALso i just put my old H pipe back on w/o cats b/c i had my to put my h pipe with cats on last month for emissions. Hopefulyl somenoe can help. Thanks

88mustanglx

where exactly is the spot to check to see what my fuel pressure is?

stanglx2002

you might want to see if your O2 sensors are any good. to check them unplug them and start the with them unplugged and see if the car runs better without them and if it does then the problem is your O2 sensors. i had that problem and i just fixed it

NeFiLiM

stanglx did you check engine light come on with a good amount of the pedal pressed down with ur bad o2s?

stanglx2002

no it didnt why?

NeFiLiM

i get a cjeck engine light when i give it a good amount of gas and have read it could be bad o2s

stanglx2002

i would check them i had one bad so i didnt get a check engine light but i changed them both anyways

NeFiLiM

can you actually drive the car while there unplugged? just wodndering os maybe i could check that way.. i think they need to be replaced witherway but yeah

stanglx2002

you can but i dont recommend it. just start the car with them unplugged and is if the car runs better or not

roundman

look on the main fuel line where it comes up on the passenger side behind the alternator. there is a Schrader valve located in the metal block that you can connect a fuel pressure gauge to to check the fuel pressure. (Schrader valve looks like a tire air valve)
you can remove the valve and screw an adapter into the threaded hole if you cannot get a gauge to fit the Schrader valve. bleed the fuel pressure off the system first before trying to unscrew the Schrader valve so you don't spray fuel all over the place!