Hello. I have 99 Ram with a 5.9, about 145,000 miles on her. She's been running fine. Regular maintenance since I've had it, and I drive it pretty easy. Today, after I got gas, I took off, but put it in second, instead of drive. I drove down the highway a few miles, and everything seemed great. But I glanced up to the ECO light, and it read 10 MPG. It usually reads about 17.3 or so, so I looked at the dash. Sure enough, it was spinning at about 4,000 RPMs. I checked, and sure enough, it was in 2nd. I put it into drive, and everything was normal. Truck runs great, normal reading on MPG, and plenty of power. I drove the next 60 miles home, got off the highway, and noticed that it has a hard miss. It still drives ok, and seems fine at highway speeds, but something was not right. When I got home, I put my hand over the exhaust...not sure why I did this, but every second or so, my hand was sucked into the tailpipe. Other than oil changes, filters and air fitler, I haven't done much to this engine since I bought it about 10,000 miles ago. All of my diagnostic tools (and most of my hand tools) are at my other place, about 100 miles away, and I won't get back there until tomorrow night. Anyway, thank you in advance!

 

Update: Last night, the engine threw a CEL for misfire on cylinder #6 (P0306). It is in fact missing constantly, not just at idle as I originally thought. Since I need to drive 100+ miles today, before I diagnose it, I'll dump a can of Seafoam in the gas tank. When I get home, I'll put a spark test light on first, if it passes, I'll use my noid lights to test the FI pulse,..then listen to the injector with my stethoscope. Then move on to compression test if both look good. I suspect I have a bad plug, wire or distributor cap, since I have no idea when it was last tuned up, but it was likely a long time ago. There is no coolant coming from the exhaust, no oil in the coolant, and no coolant in the oil, so I feel comfortable with the trip this afternoon.

 

Go home and put a cap, rotor wires, copper spark plugs ( NGK or Autolite) on it. You're probably due for a new O2 sensor (NTK) and remove the throttle body and clean it. Make sure you get inside of the IAC. You can try to clean the IAC or replace it.

 

Well, I got home, and decided to just do the diagnostics before tuning it up, since it's all so easy to get to. Noid light confirmed pulse, stethoscope confirmed operation, and spark tester confirmed spark. The spark plug was dry, and looked normal, and had no gas smell, so I moved onto the compression test. 50 psi on that cylinder. I have to assume there is a stuck or burnt valve.

The engine has good oil pressure, and doesn't use a drop of oil between changes. I check the oil every time I fill the tank, so I notice any usage pretty quickly. SO, the engine is worth a top end job, for sure. This truck is my daily driver, and I drive it a lot! I have a farmstead 100+ miles from my office, and another home about 40 miles from the office, I drive about 750-800 miles per week, with occasional fairly heavy loads up to probably 900 lbs.

Is there anything that I'm missing here with regard to un-sticking a valve, before I order new heads?

 

Do a cylinder leak down test. (requires a gauge set, and an air compressor.) That will tell you where the compression is going.

Replacing the heads is a MUCH better 'fix' than rebuilding them......

 

Agreed on the replace/rebuild option. Without a decent machine shop, it's impossible to beat the price of a set of replacement heads. And as I remember it, these Dodge heads had some cracking issues. My experience with rebuilding engines dates back to the early nineties when I worked with a racing team (dirt track), and we avoided Mopar, partially due to the head issues...but rebuild costs were prohibitive vs the Chevy small blocks. . Haven't messed with it since. I'll have to order a leak down test kit. I'll take care of the test probably Tuesday. The truck still runs very good on the highway, which is surprising to me, but I'll take it!

Thanks, HeyYou!

 

I ordered a head gasket set and a new set of head bolts. I was surprised that the service manual didn't say to replace the head bolts. Did Mopar not use yield to torque bolts? What else do I need to buy, while I have the top half of the engine off? I figure while it's out, I might as well take care of any PITA items...So far, I have the following planned:

1. New hoses all around
2. New thermostat and housing
3. General tune up
4. Clean TB/IAC
5. Of course, all of the gaskets
6. Vacuum components as needed.

 

Have the heads checked for cracks. Either that, or just replace them with some NEW, aftermarket, better castings.

 

Yep. new heads will definitely be installed. Any recommendations on heads? There's a lot of junk in the aftermarket realm...

 

Clearwater, or Odessa have the new castings for around 600 a pair. You can maybe find a better deal, just check ebay, and pay attention to the vendors feedback.