Ugh, I'm getting a cylinder 4 misfire on pretty much every cold start in the last week in my 2003 Disco. Blinking SES light, then steady. After about a 45 seconds, I turn off the engine, clear the code, and re-start, and all is good. No light, and no rough idle. I'm paranoid about a cracked block or head gasket but I have no smoke, no coolant loss, and steady temperature all day long. Please give me hope that my engine is OK.

Plugs & wires will be my first move but it might be a little while before I get to it. Is it alright to continue using the truck? If I clear the code every time and restart the engine?

 

 

Yea, good call. Thanks. Will probably just gather parts and have a shop replace...heard a lot of horror stories about replacing coils on these especially with SAI.

Any reason I shouldn't go for cheap parts like Kingsbourne wires & eurospare ignition coils? I'm always hesitant to use fancy parts just assuming it will blow up one day soon

 

Follow this link,
you might be able to do it yourself.
Kingsborne are quality wires but if you want something expensive go for Magnecor, Im not sure if you will be able to tell the difference with performance
Cheers

 

Kingsborne are good quality and should be a safe option. Any of the cheap coil packs will be fine -- there doesn't seem to be any reason to overspend on those. You may as well do plugs while you're there too. General consensus is that Bosch plugs will foul within a few thousand miles so NGK Platinums are the ones to go with. If you keep the coil packs in the original location instead of relocating them, be certain that all of the mounting bolts are tightened properly to ensure good grounding (three bolts per coil, and four for the bracket that attaches the coils to the engine block and manifold). Poor grounding can cause all kinds of misfire problems and is a pain to diagnose.

 

Take a look inside cyl 4 before you spend any money just to make sure there is no coolant inside. A tiny leak can cause that misfire, If it is coolant, it is probably being burned off until you shut it down, then it can collect which leads to the misfire when you restart it, until that burns off... In this scenario, eventually the plug will foul and cause more frequent misfires... If there is any sign of coolant in 4 you could possibly have a block issue and if that is the case spending money on a tune up will get you nowhere. .

 

#1 fear, keeps me awake.

 

Interesting development: before cranking one cold morning late last week, I popped the cylinder 4 wire off the plug, blew into the wire, plugged it back in, and she started up like new.

I've taken to doing this before every cold start (typically after sitting every night) and it hasn't misfired after doing this at all.

Good sign that it's more of a wire issue and not a coolant leak? I still haven't had a chance to pull the plug or chem test the block.

Also, for the chemical block test, how do you avoid contaminating the test, since the radiator return shoots the coolant into the top of the expansion tank? Any tips here?

 

Plug wire, that process would do zero if you have a coolant leak, I would suggest you try this:

• Remove the plug wire
• Take some fine sand paper or steel wool clean the inside just a couple of twists
• Make sure you clean the inside with a dry cloth after
• Wipe down the top of the plug
• Pop the plug wire back on - the Disco should start fine
• Next morning do nothing just try starting with luck she will just start up

A fouled plug can cause a misfire and some times it goes away with heat. But my bet is bad plug wire, either arcing or the connector to the plug is bad.