I have a 98 f150 with a 4.6 with the number 4 cylinder missing and wondering if the injectors are a common problem

 

Injectors are very reliable in these engines. If it's been a while i would change the plugs.
I had a miss after changing the plugs and new set of motorcraft wires fixed mine.
Also check and make sure you don't have a heater hose leaking onto number 4.

 

Also have a 98 w/a 4.6... And please take my advice. I fought a misfire in mine for a year... Tried Autozone, Oreillys, and Advance Auto plugs and wires... Misfire would go away for a week, maybe a month.. Then come right back...

The I got smart, bit the bullet, and bought OEM Motorcraft plugs and wires, been going on a year, no misfires, truck runs better that it has in years...

Bottom line, and everyone else here will tell ya, with any electric part on these trucks, go OEM!!!

 

Let's analyze that for a moment...

If aftermarket quality was crap on all of these various products you tried, that would make for a lot of returned parts and money lost. Since they're not in the business of making parts designed to be returned, I'd say your statement is less than accurate.

With wires, always opt for the higher grade at your parts store. NAPA sells wires made by Federal Mogul (rebranded as NAPA). Advance has Autolite. Either one is outstanding quality. The more important thing is properly routing the wires to minimize them contacting each other. When two wires are in contact, there's always the risk of a cross-fire developing.

For coils, it's a matter of using a trusted brand. Not from eBay!

With plugs, stick to the trusted ones. Certain engines don't react well to odd plugs such as Bosch platinum or E3 and can develop a misfire. I've had excellent results with Autolite XP. It's a finewire iridium plug that delivers a more focused and consistent spark. I recently had an experience with Motorcraft vs. Autolite XP plugs in a Mercury Marauder. It had a misfire at low rpm under a load. Replaced the plugs with Motorcraft and the improvement was slight at best. Ran a compression test to make sure it wasn't a major issue, all was well. Decided to throw in the Autolite XP plugs since I had them laying around waiting for another vehicle. The misfire was 95% gone. It turned out that there was a weak coil, but the electrode design on the Autolite XP was able to make a good spark with less energy.

The only downside to finewire iridium plugs is gapping them. You have to be careful not to damage the center electrode. It's never happened to me, but I can see it happening if somebody wasn't paying attention.

I would avoid NGK iridium plugs in this engine. I tried them many years ago when I owned a Mercury Marauder (different one than mentioned above). They caused a rough idle and random misfires. But they worked just fine in my Lincoln LS V6 that I had at the same time.

 

EsJayEs,

Yeah, it was a lot of wasted time and money, that's I recommend going OEM from the start... Maybe you've had different experiences as far as off brand parts go, but I'm know many here will say if it's electrical, go OEM...

 

thanks for the help i found water in the boot on wire and around the plug but not sure how it got there had no leak and i also have motor craft plugs and wires

 

Heater hose just above that cylinder is leaking. Replace with a motorcraft hose