rough idle and a miss, help

[explorer4]

i have a 92 explorer, and recently is seemed to have a miss crusing at 2000 rpm, it now is getting worse and is surging and missing badly to the point where it jerks the car. Also when i get off the gas and come to a red the rpms drop way down and i get a CEL, sometimes it will stall too. what can this be, how can i find out what code are coming up.

 

[WyoExplorer]

Have you checked the PCV valve?

 

[explorer4]

i have a new fuel filter, pcv, cleaned mass air, throttle position sensor has been checked and is ok, but i think is still is broke maybe

 

[toad]

Yea could be alotta stuff but it you get O2 sen,s codes from CEL look at the fuel press. regulator thats what happened to mine. oh yea sh!tty milage also.Good luck

 

[Alec]

Could also be a vacuum leak, a melted plug, or other problem caused by your nitrous.

Get your codes read and tell us what you find.

 

[explorer4]

how do i get my codes read, i dont have a plug under the dash, its not the plugs i checked them

 

[Alec]

Explorer4, you have an OBDI computer, so the code readers are cheap. $30 at Autozone or Walmart, a Ford OBD I computer code reader.

 

[410Fortune]

92 Explorer Sport = EEC-iv

the diagnostics hook up is not under the dash, it is under the hood over near your power distribution (fuse) box.

Read the book that comes with the $30 code scanner.
Then pulling the KOEO codes is a snap.

This is the best place to start.
If this does not work or you dont think the codes are correct (could just be realted tot eh real problem) then do what Ford would do:

Run a fuel pressure test
Run a vacuum test
Test for spark

The lower intake manifolds get loose on the pre 94 OHV 4.0L's which can cause a big time vacuum leak and all sorts of problems.

Fuel pressure test will tell you a lot, could be pump, 02's failure, or pressure regulator.....
Of course with nitrous it could be a complete meltdown...

 

[Mctrout]

I would check if it is a head gasket, as those are the same symtoms I had before the gasket went. Any white smoke in the exhaust???

 

[explorer4]

i got rid of the bad idle and almost all of the miss, the only thing is i have an oil drip in the front of the engine, i havent found it yet, i can smell a little bit of oil from in the car, but my dad couldnt smell it. anyone have any ides, no smokw outexhaust or oil in radiator, how hard is it to change the head gaskets, or how much would it be

 

[BAMBAMN]

what did u do to get rid of your problems???

 

[explorer4]

i redid my battery connections, but it still has a miss at 2000 rpm. anyone help?