Hey everyone first time post and really could use some direction on this one. Its seems pretty straight forward but I am down to the last possible fix that I can think of. 97 RAM 1500, 5.2/318. Code reader is showing cylinder 5 misfire. Ive change plugs, wires, rotor and cap. Compression is good on all cylinders. Spark is good and trucks runs. Ooo… and check engine like is on due to miss fire. My next step would be to get head/valves done. What do some of you guys think? Thanks with any feedback any of you guys can offer.

 

Do a cylinder leakdown test. (need the correct gauges, and an air compressor for that.) See what the numbers look like, and where the air is going.

Don't waste money on the stock heads. Replace them with new, better castings from someplace like Odessa Cylinder head, or Clearwater. (actually, the same company.....) the have NEW heads with thicker decks that are far less prone to cracking.

Also, have you fixed the plenum yet? (see stickied thread at top of this forum.)

 

I recently got off the phone getting pricing for a new head, solves, and springs. I should have said replacing the head instead of valves. I am really looking at a new head. Thanks for the reply Super Moderator this reinforces my thinking of replacing the head. As for repair of the plenum, no I have not done anything with that and did know anything about it until today and I don't know what to repair. I will have to look that up to learn about that and were its located. I think its under the intake but tell me if I'm looking in the wrong place.

Thanks again the info is very much appreciated.

 

Yep, under the intake. Read thru at least the first couple pages of the thread. (80 plus pages by now...... maybe if you have a quiet evening, with nothing better to do. ) I would deal with the plenum, and possibly timing set before spending the coin on heads. I would also want to do the leakdown test, to see if there is even really a problem with the valves...... If it ain't broke, don't fix it.

 

Okay did some reading on this Plenum and relationship to my issue and it sounds like the Plenum is should be changes anyway even if its for preventive maintenance. My question is what are the symptoms of having a problem with the Plenum gasket? I just may go ahead and change the Plenum gasket and the head. Just thinking if thats the right thing to do.

 

I don't mean to rain on your replace the cylinder heads parade, but there are dozens of things that can cause a cylinder misfire warning on your ECM. Imagine replacing your cylinder heads and the misfire is still there. The first thing to do is to get some live data off your scanner if it can do that. Check your fuel trims at idle, 1500 RPM and 2500 RPM...only after the engine is at operating temp at running at steady load (you could have a vacuum leak/the plenum is always a buggerman when it comes to leaks...this can be done in your driveway. Pay specific attention to your intake air temp indication...the sensor could be dirty or bad. Also, check to see if your O2 sensors are operating properly. The #1 sensor/s should move up n down "constantly" in voltage, whilst the #2 Os sensor/s should be rock steady. Last but not least, have the cat/s checked for excessive back pressure.

 

Hay not a problem you can rain in anytime I can use all the advice and I will look into it. I really appreciate all of this advice it really helps me to understand the possibilities and depth of this issue that I am having. As soon as I can get time with the truck again I will start with a smarter approach by checking some real-time information and let you guys know what I find. Again chime in anytime and thanks.

 

I've got the cab of 'ol blue torn down...the floor rot is worse than I thought. Grinding away/cutting out all the old rusted thru floorboard n welding in new stuff. I think I'm getting arthritis (hands really hurt...waaaahhhh!!!, so I'm really glad for help from 1 of my sons. It is always handy to magically transport in help from cyberspace...shore beats old school, LOL!!! No to mention, gotta love those youtubers...even if they're language is extra colorful or difficult to follow sometime.

 

have you tested/pulled the injector to see if something isn't right?

 

Yes Ive moved the injectors to see if the misfire followed the ejector as well as the plugs. Changed wires, distributor and cap. All of that was much needed anyway. As stated above compression is very good in all cylinders thats what make me think about the head/valves not seating corrected producing a misfire.