Ideas for issue that started today - engine starts to stall when in gear

[Kagato]

So my 94 R/T has been running like a champ until this morning. As I was accelerating to merge onto the highway on my way to work, the car felt like it just wasn't getting up to speed like I'm used to, and for a moment felt like I was driving on a gravel road. Soon as I got up to 70 all was fine - no noises, response felt fine, etc. and I continued on my way to work. As I exited the highway, I basically felt the reverse of what I felt earlier, a light vibration as I came to stop and then the engine power felt like it was fading. Once I stopped at the light, the car started idling very low to the point of near stalling, and I noticed all the instrument panels were dimming as well. Fortunately I only had to drive a few blocks from the light and made it there without a stall.

I had a couple of minutes during lunch to go out and give a quick one-over to make sure nothing had come loose etc. and couldn't find anything though I do need a closer inspection of belts, etc. I noticed that when I fired the car up, it runs fine in park, but as soon as I shift to any other gear (reverse, drive, etc.) the same issue starts up with the car nearly stalling and feels like there's vibration - don't know if this is because the engine is idling so rough or not.

I was originally thinking perhaps either the idle air controller or tps, but that would be a constant whether the car was in gear or not right? I'm dreading to think that it's something transmission related :confused:

Any other ideas? Specifics I can give? The only thing I did different today was gas up before heading out - there wasn't a hint of any issues on my drive home from work last night.

**Addendum from later post**
It was still acting up on my drive home from work this evening. The wierd thing is, as long as I was on cruise control, everything was fine, even at up to 70mph. It's just the acceleration where the engine almost seems to be retarding itself. When I first press on the gas from a dead stop it almost feels like it's choking itself - then it'll go fine for a couple seconds, choke some more, and repeat up until I'm at a constant, cruising speed. Am wondering if there couldn't be an issue with the torque converter - though that typically wouldn't cause idling issues would it?

[MaxClass]

I would check electrical. Make sue your alternator is putting out more than 12 volts and that the battery is fully charged. If all that checks out then you have a solid foundation to start looking elsewhere. Could be plug breakdown due to running on battery but thats just a WAG.

What year and model (guess NA) is it and could it be an ECU issue with leaking caps. If they haven't been replaced they can cause a multitude of issues that seem like something else.

Putting the car in gear puts it in a 'load' condition that requires more spark and fuel. Also think about the fuel filter as another possibility.

Just my 2 cents. Hope it helps.

[Steve '92ES]

The only thing I did different today was gas up before heading out
Could it be as simple as that.. a tank of watery gas?

[Kagato]

Could it be as simple as that.. a tank of watery gas?
I had thought about that too, but the fact that it seems to be idling fine while in Park kind of killed that train of thought for me. I did crack the window while driving just to see if I could hear pinging in the engine and it sounded normal - though I suppose trying to judge that while sitting in the driver's seat is a far cry from being right next to the engine.


I would check electrical. Make sue your alternator is putting out more than 12 volts and that the battery is fully charged. If all that checks out then you have a solid foundation to start looking elsewhere. Could be plug breakdown due to running on battery but thats just a WAG.

What year and model (guess NA) is it and could it be an ECU issue with leaking caps. If they haven't been replaced they can cause a multitude of issues that seem like something else.

Putting the car in gear puts it in a 'load' condition that requires more spark and fuel. Also think about the fuel filter as another possibility.

Just my 2 cents. Hope it helps.
It's a 1994 Dodge R/T (NA). So far as I've been able to tell, alternator and battery seem to be just fine. Worked a late shift this evening and don't have the energy to poke around with it tonight. I was thinking about the ECU and have always worried about it given the age. I had taken it out late this past summer when I was swapping the drivers seat for an electric model. None of the caps appeared bulged, didn't detect any rotten egg/sulfur type smell, and there wasn't any discernible acid damage to the board that I could see. Granted I know that doesn't mean there still couldn't be issues with the caps. Has always been one of those "to do" items.

Hoping to get some time before work tomorrow to check out the spark plugs and cables and see if there's anything fishy going on there.

It was still acting up on my drive home from work this evening. The wierd thing is, as long as I was on cruise control, everything was fine, even at up to 70mph. It's just the acceleration where the engine almost seems to be retarding itself. When I first lay on the gas from a dead stop it almost feels like it's choking itself - then it'll go fine until 15-20mph, choke some more, and repeat up until I'm at a constant, cruising speed. Am wondering if there couldn't be an issue with the torque converter - though that typically wouldn't cause idling issues would it?

[IPD]

iirc, when my iac went, it idled fine in park. it only went crazy when it was in gear. but it's been several years.

[Kagato]

iirc, when my iac went, it idled fine in park. it only went crazy when it was in gear. but it's been several years.
Yeah, it's probably been 6+ years since I last replaced my IAC and I don't recall all the specifics as I was on the road at the time and the car died as I came to a stop. The IAC wouldn't interfere while actually driving at highways speeds though would it?

Unfortunately we've got snow/ice hitting the area today so I likely won't get time to do much until the weekend. Keep wondering if it might be a spark issue, but it'd seem odd that it'd only impact during acceleration and not once I'm driving at a constant, cruise-controlled speed.

[IPD]

could be spark plugs. iac will only effect idle.

[x2percentmilk]

^ had similar symptoms, my plugs were toast. vibrations occasionally at highway speeds, but mostly at lower speeds.(crazy scary vibrations, would come sometimes after WOT or just randomly, not too often). car generally felt rough, and would almost stall during idle occasionally.

[speedy25]

From his description it is an idle problem. Check IAC and clean the TB where it bolts in. It doesnt take many deposits to make it erratic.

-SP

[Kagato]

From his description it is an idle problem. Check IAC and clean the TB where it bolts in. It doesnt take many deposits to make it erratic.

-SP
Added addendum to my original post with a reply I'd posted about the drive home the same day. The car not only runs rough at idle, but during acceleration, has wierd bouts with hesitation and an odd vibration. As soon as I'm at highway speed and on cruise-control, it runs fine.

Temperatures are supposed to really spike back up this weekend so I should get plenty of time in the garage to do a little bit of teardown and cleaning and try and track down the issue. Thanks to the responses thus far - will give me plenty of things/areas to check.