No spark on number four plug

4 spark plugs.

Change the spark plugs first and see if it improves.

Hi T:
Interesting as smooth idle and sputter are contra-indications.
- Smooth idle should be healthy
- Sputter could indicate problem:
- mis-fire? Possible bad spark plug or bad exhaust valve. Pull spark plugs to check to see if any are fouled. Compression check will help depermine why fouling is happening.
How many cylinders?
How many Km on engine?
With engine hot, Remove oil filler cap and see if any vapour indicating blow by (bad rings)
My suggestion?
Do some more checking and reply as a comment on this post. Will assist if I can.
Cheers.

Here are a few things that might help.
1. Check your spark plugs. make sure the gap is right and they are not worn out.
2. Check your distributor cap and rotor for build up on the contacts.
3. Check your spark plug wires, make sure they are on the distributor and spark plug tightly. also check them for damage ie. heat, knicks, scrapes, etc.
4. intake idle control valve. these do cause your symptoms and are easy to replace.

hope this helps ~ Zach

Is the engine running VERY smooth at an idle? if it is not , and I suspect it isn't, then you crossed 2 spark plug wires.

You have two coils on this engine. Test each wire for spark with the engine running. You'll find at least one wire not sparking. replace the coil that has the wire that's not sparking.

Replace the fuel pressure regulator.

please say you did not get the engine steam cleaned...as you can cost yourself a LOT of money.hopefully the heat will dry things out, otherwise get the car put on a diagnostics machine.

Check number four spark plug. The gap could be off causing it to mis-fire.

If it's the four cyl., the first coil pack bolts over the #2 spark plug. The #2 coil pack wire plugs into #3 spark plug. The number two coil pack bolts directly over the number four spark plug, and the #2 coil pack wire plugs into the #4 plug. The firing order is 1-4-2-3.