more symptoms + backfire

[Tarik916]

The problems below just started after a lower manifold gasket change a few days ago...

One minute it drives fine, the next is starts to buck and the RPM's drop and I lose all power for a few seconds. The car feels strong until this happens. All the sudden it goes to downhill and bucks and backfires until it shuts off. When I try to keep it alive, the RPM’s keep dropping. There is also a delay in me tapping the throttle and the RPM's climbing.

I changed the vacuum lines, spark plugs, cleaned the sensor on my mass air and checked for leaks in all of my vacuum lines and intake pipes, but still have the same problem. My timing could be a little off, but I don't think it would cause a dramatic change in behavior one second to the next.

When I started up the car (cold), it sat at idle for about 10-15 minutes and seemed to idle ok, all of the sudden the RPM's dropped to 500 and began to change erratically, my vacuum went from 20 to 10 and the car died. I started it back up and it idled for a few seconds then the same thing happened except it started backfiring so I shut it off.

Please HELP or the mustang get's it.

 

[shogun]

maybe your throttle position sensor?check the voltage.

 

[ADRENA LYNN]

Sounds like a coil going bad. Or possibly time for new Cap and Rotor? how longs it been since changed?

 

[Rootus]

Well, since the TPS wasn't changed, let's skip that for now, eh? I do not believe in coincidences.

I'd re-check all the vacuum lines very carefully. It would take a pretty big vacuum leak to cause those symptoms, and I would expect it to be full time.

And I'd check the wiring on the MAF to make sure it's making good contact after you put it back together. Something wrong with that will definitely make the car run like crap.

Dave

 

[final5-0]

Tarik

Most likely something simple you have overlooked.

Recheck everything you messed with.

Sounds like a v leak but don't tear it apart until you check all the easy stuff.

When your idle gets bad and v readings drop you might try to spray a small amount of starter fluid around a suspected v leak area to see if idle jumps up.

Good luck!!!
Later
Grady