Cause of mis fire on RAM 1500!

[idrivemopar]

I think this is the cause of the misfire codes on a 2002 RAM 1500 4.7 I am working on for a neighbor. These are the two plugs from the cylinders with specific misfire codes, but the rest of the plugs are not much better and probably why its also throwing a general misfire code P0300. I have never seen plugs this worn out before, guessing they have never been changed!

Just curious if coils on each plug should be replaced, looked around for some testing, and not certain about it, so if anyone has any recommendations to test with VOM, let me know.

 

[Daves69]

4.7 Calls for plugs every 30K on A and B schedules I believe.
If the plugs solve the misfire no coil change should be necessary.

 

[65-440]

Leave the coils alone, plugs should do the trick. Clean that throttle body while you're at it, they get nasty.

 

[WP29440SE]

What ever you do , don't upset the TPS or IACV, it will never run the same. I'm currently doing battle with mine

 

[idrivemopar]

Just keeping it simple, so not going to be messing with either of those.

 

[Kern Dog]

I had a 2002 Ram with the 4.7. I went 163,000 miles with it before I sold it. The truck still ran and drove great but I wanted a 4wd. I changed the plugs about every 30,000 and they had worn electrodes like that, though mine never ran rough or threw a code.

 

[bm02tj]

Use the champion plug listed on the emission decal gap as required
It will run better than any other brand
I thought that was bunk when a friend told me that till I proved to my self

 

[65-440]

Just keeping it simple, so not going to be messing with either of those.

You'll be fine, brake clean and an old tooth brush is all you need. You'd be surprised how much better the truck will idle with a clean throttle body and iac. The only time you will screw a throttle body up is if it's drive by wire and you use something other than brake clean, the solvents will seep into the motor and cause damage. Brake clean is safe, plus 2002 was still cable driven.

 

[PurpleBeeper]

You'll be fine, brake clean and an old tooth brush is all you need. You'd be surprised how much better the truck will idle with a clean throttle body and iac. The only time you will screw a throttle body up is if it's drive by wire and you use something other than brake clean, the solvents will seep into the motor and cause damage. Brake clean is safe, plus 2002 was still cable driven.

Ooooo.... there are A LOT of different brake cleaner formulas & some of them will eat some plastics. If your throttle body is all metal, then no worries. If you can find one that's 100% heptane or hexane + propellant you'll be fine. If you see a brake cleaner with acetone (or any other chemical ending in "one" - aka ketones) I would not suggest it (on plastic).

To Idrivemopar - Yeah, these guys are right. Change all the plugs & I'd suggest a good fuel injector cleaner at the same time since a mis-fire can be fuel related too. Looking at those plugs, I'd say that's likely your problem with P30xx codes.

IF you still get a code on one cylinder, say P0302, THEN look at injectors. A trick I use is to switch two injectors, clear the codes and see if the P0302 code changes to a P0303 code (for example) following where I put the injector in question.

 

[idrivemopar]

Looks like the new plugs did the trick, she runs smooth, loud and proud, it has a single exhaust with just a resonator, and she blows nothing but water out the pipe, and gets up and goes now. A far cry from before, where it felt like she was gonna stall and barely had enough power to pass another car! LOL Im still amazed at the wear on the plugs!

 

[not so famous bob]

Looks like the new plugs did the trick, she runs smooth, loud and proud, it has a single exhaust with just a resonator, and she blows nothing but water out the pipe, and gets up and goes now. A far cry from before, where it felt like she was gonna stall and barely had enough power to pass another car! LOL Im still amazed at the wear on the plugs!

I changed my first set of plugs on my 02 ram quadcab at 96,000. It`s got 161,000 and some change now. Think I should change them again ?

 

[Daves69]

Think I should change them again ?

na