RAM just doesn't seem right - any ideas???

[Z06]

I've got about 42K miles on the Ram now. Did a minor tune up (plugs, air filter, oil, etc) at 30K. About 6 months ago, I did the TV cable adjustment, but since have set that back because it was too touchy for downshifting. Anyway, to get to my problem, when I start up in the morning and let the truck warm up for a few minutes, after say maybe 2-3 minutes of idle, the truck will start to run fairly rough (shakes, and sounds like it's got a hot cam in it). If you rev, it will sort of stumble, clear, and then go back to rough idle. After another minute or so, it clears up and idles fine. Weather pretty much isn't a factor as I've seen it happen warm and cold (but at first start of the day). Seems like it must be a sensor that is coming on line as the computer goes from closed loop to open. Also, the truck just seems WAY down on power. On a recent trip to FL, had the cruise set on 78 or so, and the truck couldn't even pull a slight hill without a kickdown (which the cruise did for me). Seems to still have to downshift at slow speeds (from 3-2) for even slight acceleration. Mileage is also WAY down. I am getting about 305 miles out of a tank...roughly 14 on the highway. Again, trip to FL, pull over, fill up, ease back on to interstate, set cruise on 78, and run till the light comes on...that normally will yield best MPG. I know for a fact I've gotten WAY better than that on the highway (at least close to 400 miles). The truck is stock except for 265/75 tires (which I know cost me a little in perf and MPG). IDEAS???

[Ram-N-Time]

Are you using more oil that usual? If you are, I would check your intake plenum cover gasket. A quick way of seeing if that gasket is bad is to look down your TB. If you see a lot of oil down on the intake floor then your gasket has blown.

Do a search, there is a lot of information on this subject.

[Z06]

I thought about the blown plenum gasket, and right before my last oil change had dropped about a half a quart, but I changed oil about 3 weeks ago and have put almost 1500 miles on it since and no oil usage (at least when I checked before the trip last week). I'll take a look just to make sure.

[Carnivore]

could be clogged fuel line, injectors, valves. Put a can of BG 44k into your next full tank and don't fill your tank up again until it is at empty. The 44k is expensive ($22 a can) but the stuff really works)

[NTENSE99]

I had the dealer change my O2 sensor within a month after having my plenum gasket replaced. I think the leak from the plenum could have prematurely fouled or killed the O2 sensor.

I was exeperiencing major lack of power, excessive downshifts required to pull hills, and poor MPG. However, I did not have the cold start stumbling you describe. I got a decent amount of power back after the O2 replacement. I wasn't certain if they replaced only the front sensor, or both, but they both looked new. From what I've read here on MC, the front O2 sensor has the most affect on performance while idling or cruising at steady speed. The one after the cat. tells the computer if the cat. is functioning OK.

I'm no expert, but I'm not sure why you are getting bad idle, then good idle after the O2 comes on line (if that's even what's causing your problem). It seems it would be the other way around.

I wonder if your IAC valve/throttle body needs to have the carbon cleaned out?

You might also want to pull the plugs and check for either oil or carbon fouling.

Have you ever replaced the cap and rotor?
At your mileage, it might not be a bad idea. At least check to see if the tips inside of the cap are developing corossion or if the rotor tip is getting electrically worn. Mine had both symptoms at 35,000 miles. (Less than a $15 deal for NAPA Echlin Brass cap and rotor.)

After my Wires, cap, rotor, and indexed Autolite 3923's, my truck seems to be occasionally shaky at idle, but smooths out after a couple minutes of warm up. It started out seeming smoother after the cap, rotor, and wires, but has now developed this minor idle shake, but it doesn't really bother me. I have a decent amount of go power and reasonable (13.5 MPG), but not outstanding MPG (was 15 MPG), considering I have a ping flashed truck. I attribute the improved go power to my K&N Gen II. I attribute the lower MPG to the ping flashed PCM.

NTENSE99

[moparye]

Mine will do the same thing every now and then. A few minutes after the first startup, I will hear air start sucking more through my KN filter and it will idle rough. All i do is rev her up and then its fine. No notice on power loss. Any other ideas? Thanks

[fastermopars]

Is your fuel economy worse than it normally is? If so, the o2 sensor could be the problem.

fastermopars

[kevinrichards]

I'm sort of experiencing the same problem. Just changed my oil and it's used a quart in about a month and a half. At 16000 miles, could my plenum gasket be bad? I have never gotten decent gas mileage, usually around 10 or 11.

It is rough as can be starting up in the morning, year-round. I have to back out of the garage and down the driveway, and it makes a loud grinding sound almost. The K&N filter does make a lot of noise at start-up, same as Moparye said. I'm confused on what would do this, but as soon as I put it in drive to go up the hill by my house, it doesnt make the grinding sound.

BTW, did the TV adjustment today, it was worth it. Now i can hit 3000 rpm before it shifting without flooring it.

Thanks

Kevin

[moparye]

Nope. fuel economy is the same. Just the idle seems to be the problem on startup. To me it feels like its getting too much fuel at the time and halfway floods the engine, thats why it clears up after I rev her up.

Z06-
Mine as well seemed to kick down a little too easy with cruise on, but after my KN and exhaust, the truck very seldom has to kick down anymore, pulls fine. Later

[biggerhammer]

check the O2 sensors and the cat.

[Carnivore]

Kevinrichards,

The loud noise when backing up is normal. I had my truck in for that when I first bought it and they said that is a normal sound for the tranny when it is first placed in reverse after being of for a long time. Something about the fluid being recirculated.

[Z06]

I'm thinking more and more it is the O2 sensors. Could also be the cat, but it seems kinda early at 42K. Actually, I am 99 percent sure I only have 1 O2 sensor. I've got the cat that has two pipes coming in from the manifolds, and then one out. If it turns out that this is the problem, I'll probably just go with a high flow unit anyway. Thought I had also read it could be a bad TPS?? Noticing more and more that the rough idle is pretty much there all the time until she warms up. I'd agree with the comment that it sounds more like it is flooding than anything. That has to be computer related as a sensor is telling the injectors to spray way too much gas. Are there any on board diagnostics (codes) that I can pull to check for faulty O2 or TPS? Even some basic diagnostics with a digital meter?

[kevinrichards]

Thanks for clearing that up! It gets really loud sometimes, and I was kind of concerned.

thanks again

Kevin

[Carnivore]

Welcome. by the way, how did you like your TV adjustment? I am about to do that this weekend.

[Buckshot]

My 97 GMC had the same problem, only the ruff idle was there from the crank, and ended a few minutes later. Turnes out, I didn't tighten my throttle body down tight enough, and air was leeking in. I tightened it up, and everything was fine. Maybe you have the same thing?

(also, the VORTEC box on top was loose, so air was getting in through there also).

Good luck!

[JeepMan_Iowa]

It might be your Idle Air Stepper (IAS). It may just need a cleaning.

Remove the IAS from your throttle body and clean the plunger with carb cleaner. Do not push the plunger in.

And if that doesn't work, then you may need a new IAS.