Hey everyone, new to the site. I have a 97 dodge ram 1500. It has the 318 5.2 in it. A couple weeks ago i was going down the road in 4wheel drive, becuase it was slippery. Then my truck started to die so i let off the gas, then it recouperated, and then did it again when i tried to press on the gas. It did this for about 1 mile then went back to normal. I looked into it but then shrugged it off. Now three days ago it did this again. It started with a really hard start, and then died a few times before i could pull out of my driveway. Once i got it going i noticed a small loss of power, but not too bad, figured i had bad traction. This was when i was only trying to go 30 mph down a flat surface. Then i turned onto a county road and tried to accelerate. I was pushing the gas almost to the floor and i was getting no response out of the engine, it was dieing almost it seemed, but then it shifted down and the rpms shot up, allowing me to accelerate. But let me get something clear, I accelerated very slowly, although the throttle was pinned. It acted like this for a while and then the next day same thing, hard start, dies, then start again. This time i was trying to drive up a hill, and then it started dieing and backfiring. So i thought what the heck. I replaced the plugs and had a look at the distributer last night but that wasn't the problem. Perhaps Intake gasket leak, or the fact that i have an O2 sensor out. It's the first O2 sensor , no the second. I would replace that but the O2 has been out for 5 months and haven't had problems since. It's gotten to the point where i can't drive my truck over 10 mph, without it dieing, backfiring constantly and getting 3-4 mpg. I also had thoughts about timing chain, but i've been told otherwise. I plan on taking it to a shop and paying the diag. fee, but they charge 99 an hour labor on that. Any input would help. Thanks.

 

i think it might be a slipped tooth on the timing chain. the plenum gasket has some of those symptoms but arent quite as severe as that. pretty sure the o2 wouldnt affect it because if the o2 is missing the engine will run rich to prevent burning valves. anyone else got some input?

 

I noticed you mentioning that you had the first o2 sensor out, is it removed entirely or has it been replaced? If it runs good with the pre-cat o2 out, chances are your catalytic converter is clogged up. If that's not the case, the IAT sensor or the coolant temperature sensor could also possibly cause the truck to backfire if one or both of them went bad.

 

The pre 02 has been removed completley, i wanted to remove the Cat, to reduce resistance in my exhaust. Incidentally, the "Pre O2" sensor was on the cat and when i removed it the truck ran fine, a bit rich. Now the truck is in the shop and im waiting for a diag. I get a engine code , High voltage in O2 Bank 1, which isn't that big of a deal. My charcoal cannister is also out, which caused a vacuum leak in the engine. I promptly removed both hoses on the Cannister and plugged them with bolts, which removed that code. Yes, i realize that this cannister should be replaced, but as of this moment that isn't a priority. The thing is, my truck runs great in idle, and if i revv it up it sounds great too. The only problem is when i'm trying to go forward. It will sputter and start to die, backfiring under load. Thanks for the suggustions i'll post what the shop diagnosis in a bit.

 

You should never remove the front O2 sensor. The rear O2 sensor detects the status of the converter, the front has nothing to do with the converter. The front sensor (pre-cat) detects the oxygen in the exhaust and helps the computer run the engine efficiently. Without it, you have been running in "open loop" mode, which means the default programming (no learning), meaning wasting fuel and causing extra wear on your engine parts. It can also cause problems with the other sensors on the engine can't compensate for the lack of the pre-cat sensor.

Put the pre-cat oxygen sensor back in (drill out a hole if you have to) and see if it runs better after disconnecting the battery overnight. If not, then plugged converter. If so, then there's your problem.

For future reference:
https://dodgeforum.com/forum/dodge-r...s-section.html

Moving you now.

 

Not much chance of the chain slipping on a tooth. If the timing is an issue, it would nore likely be overstretched chain. But I sount that is the cause.


I suspect cat is clogged up, and the open O2 port is not allowing it to breathe enough. Mainly because of your statement that it ran fine right after that.

Remove throttle body and look down inside the intake with a lght and mirror. See if there is an excessive amount of oil in there. The capped canister is not helping you either. It would be better to tie the hoss together (but not much) than plugging.

How many miles on the truck?

 

I agree completely, that's the most likely cause of a majority of your problems performance wise, next to the possible plenum leak and carbon build up as a result. Also, as jasonw stated, it's not wise to run the truck permanently without the front o2 sensor. It is critical to your ECM's normal operation, without it you're gonna hurt your mileage and even your engine in the long run. Removing the front o2 temporarily is a method for checking to see if the cat is clogged. If it runs better that way, it just means that the exhaust finally has a path (albeit, a small one) out.

 

Hey guys heres an update. Brought it into Precision Auto for Diag. couple days ago. Got it back last night and got the write up from the guy. He said that the first O2 being out rendered the last one useless and that it needed to be replaced, as well as exhaust leaks here and there. I'll update after i replace O2 and seal everything off, either tonight or friday night. Thanks for the help.

 

160k no cat in it at all, removed when it busted.

 

Frompost #6 in this thread:

"Remove throttle body and look down inside the intake with a lght and mirror. See if there is an excessive amount of oil in there. The capped canister is not helping you either. It would be better to tie the hoss together (but not much) than plugging."

A rear O2 sensor, whether good or bad, will not cause your problems.