1999 Mercury Sable Misfiring and idling rough.

RYANJO79

MEMBER
1999 MERCURY SABLE
6 CYL
FWD
AUTOMATIC
160,000 MILES

Just last night I had my plugs and wires replaced, nothing was really wrong with the plugs when we pulled them out they looked almost new. We decided to go ahead and replace them anyways because the wires really needed replaced. So after doing all this my car is now running very poorly. It idles very rough and seems to misfire everytime you push the gas pedal. We've checked all plugs and wires to make sure they are on and in the correct spots. Wondering what my next step should be in trying to figure out what happened? It's just weird is all because it wasn't doing this before we changed everything.

1 Reply

MERLIN2021

MECHANIC
17,250 POSTS

You removed a few parts to get to the rear plugs, IAT and MAF, and you may have bumped into the throttle sensors, TPS and IAC, check all these connectors, and push the wires all the way onto the new plugs. Check EEC fuse in the in car fuse box. These are the only explanation other than a bad coil. Test spark output at all plug, one at a time. If your check engine lightis now on, read the codes, autozone reads em free, if you can't get it there, follow the link in my signature file and buy an OBDII scan tool, they read all cars sold in the USA from 96 to present.