I have a 99 Ford Ranger. I just had plugs & wires put in. The motor shimmers when I stop, but it's o.k. when I drive. What can that be?

 

Too much wax................shimmers???

Shimmies?
Motor mounts maybe but no clunking right?

Automatic trans?
If you put trans in neutral is shimmy less

Vacuum gauge is very very easy to use on any engine, and costs about $20
It can tell you ALOT about engine condition and if there is a problem.
Read here: Technical Articles: Engine testing with a Vacuum Gauge - at Greg's Engine & Machine


I assume check engine light works, but is off when engine is running, so no trouble codes

 

i think he meant stumbles when idling

 

Did it do it before the wire/plug change?
Who did it?

If 2.5 4 cyl was Intake manifold removed? Vacuum lines pulled?

I vote for vacuum leak.

 

2 solutions come to mind

have you ever replaced the rubber elbow from the intake manifold to the brake booster

they crack and leak from engine heat and the elements

did you dis-connect the battery for 30 minutes after you replaced the spark plugs and ignition wires

you have to in order for the computer to relearn new fuel trims

 

Vac leak could be it.
Also, check the output of the alternator/battery, engine/computer needs a minimum solid 13.5 v to operate properly.

 

Well jdibbs hasn't been back to check answers

So I think................he put the hood back on so engine doesn't shimmer any more