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I got a 1998 dodge ram auto with the 318 that I bought back in january. Every since i bought it, its had the same problem but has progressivly gotten worse. When I first drive my truck in the morning (when the engine is cool) it seems to have a bit of a rough idle but not bad. when I start going down the road it has a nasty missfire for a second right when I start accelerating but comes out of it quickly. After i get up to about 20 mph +/- after it shifts into second, it almost feels like im hitting the brakes and the eninge sounds like its loading up. Itll start popping and surging untill i let off the gas or stomp on it. I tried it with the A/C on one morning to see if it would act differently and it makes it much worse. The extra load on the engine loads it down even more and quicker (before it shifts into second) but once it comes out of it it drives fine untill i drive it later in the day when the engine has cooled down a little bit.
It also seems to have no power off the line. I know that the 318 isnt all that muscular but when I first bought it I had no problem getting the tires loose and now it has a hard time breaking loose even on gravel unless I stomp on it. once the rpms climb to about 2800 the engine seems to catch and it starts pulling pretty good. im also getting terrible gas milage (around 8-9 highway) I know these trucks are gas hogs but i have a 96 ram with the 360 and was getting around 12 highway.
Another problem it seems to have is loading up at an idle. Once i start it and let it idle for a little bit it starts to bog down, chug and idle really rough.
I know these trucks are notorious for blowing lower intake pan gaskets but it doesnt seem to have all the same symptoms like oil consumption. when I first bought the truck i pulled an o2 sensor code but havent scanned it recently. also, it sounds like I have a pretty nasty vacuum leak. It almost sounds like a turbo on my engine. I know that needs to be fixed but im not sure if the vacuum leak would cause those problem to happen at only those times.
I cleaned the throttle plates up, new cap, new rotor, wires look new, not sure about plugs.
any advice or ideas are appreciated
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just got done driving it with the pre-cat o2 pulled out of the pipe and it ran much worse. The power seemed to go down, really rough idle, it almost felt like it was going to die when i came to a stop, and it seems to load up more often. not sure if this is because the o2 was out and not reading right or if that could be a sign of something else causing the problem. although ive heard of this test being used ive never done it myself, ive always used a pressure gauge in the o2 sensor hole so im not sure what is to be expected.
You should be monitoring the fuel trims when the problem is occuring.
You stated before that you had a misfire on # 8. Did you ever investigate that?
Did you monitor the coolant temp sensor from cold to hot for any glitches?
I’ll take it for a drive tomarow and record the data from the drive.
I havent investigated into the misfire much yet.
I looked back at the data I recorded today and watched the ECT sensor rise and found no glitches.
took it for a drive today while the computer recorded live data. i noticed that the long term fuel trim was very erratic. I always thought the LTFT was more stable and smooth whereas the STFT was more erratic. Maybe im wrong. The o2s seems to be working like normal though. Ill post pictures of the data from when the engine was cold and when the engine was at OT. i have pitcures of the o2 and fuel trim at the start, in the middle, and at the end of the drive.
i did a little more digging today and found that the cat was gutted out. It suprised me since i bought the truck from a dealer and assumed that it would be illegal to sell a vehicle without a working cat. maybe not. i drove it again with the scanner hooked up and showed the same thing it showed a couple days ago. one thing i did notice today that i forgot mention was the vent doors. Theyre vacuum operated on my truck and whenever i push in the gas past about 35% the vents go to dash vents (defrost) but as soon as i let off, the vents go back to the normal setting. No matter what setting i have them on it will always do that. My old dodge was also vacuum operated but never did that. not sure if its a small vacuum leak or a faulty motor. any thoughts?
[quote=”sam_priem” post=65009]i did a little more digging today and found that the cat was gutted out. It suprised me since i bought the truck from a dealer and assumed that it would be illegal to sell a vehicle without a working cat. maybe not. i drove it again with the scanner hooked up and showed the same thing it showed a couple days ago. one thing i did notice today that i forgot mention was the vent doors. Theyre vacuum operated on my truck and whenever i push in the gas past about 35% the vents go to dash vents (defrost) but as soon as i let off, the vents go back to the normal setting. No matter what setting i have them on it will always do that. My old dodge was also vacuum operated but never did that. not sure if its a small vacuum leak or a faulty motor. any thoughts?[/quote]
I would suggest you check the actuators and surrounding lines. sounds like a vacuum
leak. That is not normal for the vent doors to switch.your heat/ac problem is a one way vac check valve is not working it should be located just before the a/c heat box,Lots of chrystler/jeep products have this problem.
On low vac when you give the engine throttle the blend doors move to the defrost side on higher vac they go to the setting on the dash.
Hope this helps.I’ll check into that today. I tried looking for the part online but couldnt find one. Only universal ones. Im guessing its a dealer part. Ill try swapping it with my old truck at see if it changes anything.
i replaced the 2 check valves on the vent vacuum lines but nothing improved. Im not too worried about fixing the vents themselves since i dont really use them in the summer. I use an old bus driver fan that i got rigged up by my rear view mirror. I checked for vacuum leaks again but still did not find anything. Its really starting to get annoying. im about ready to take it to a seasoned pro to at least tell me what it is but i dont want to spend the money. any other ideas?
A shot in the dark here-you have not mentioned anything about the EGR valve/system so far. If that valve is opening prematurely or hanging open it COULD cause some of the symptoms you are describing.
Also you talked early on about a noise that you said sounded like a turbocharger was on the truck. Is that noise still there?sorry for the late reply, ive been working late everyday this week at the shop. I havnt mentioned the egr system because i havnt had a reason to mention it. I havnt pulled any codes for it (not to say something cant be wrong with it.) i havnt done much with egr systems so i wouldnt know what to check. and yes the noise is still there.
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