1999 Dodge Grand Caravan suddenly sluggish

Maintenance/Repairs
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1

1999 grand caravan 3.0L approx 250,000 Kilometers / 155,000 miles

Yesterday morning I was on my way to work, highway mainly. We have some cold weather here lately, say this morning low -20c range with a light wind. I was about 15 minutes ( 1/2 way & running fine ) while into my drive when i stopped at a light ( vehicle at operating temp )… light goes green, then i accelerated i felt a slight lurch/hesitation, almost a miss but it kept going and then it seemed to be slightly over revving / under powered to get up to the typical highway speed of 80 KMH / 50 MPH in that area.

It felt a bit low on power and a bit louder than normal, i chalk that up to the fact that after the “lurch” it felt like the trans was, I don’t want to say slipping but kind of. It would settle into its final high gear a tad later than normal.

I will say it seems like it is reacting like when you accelerate on a slippery or icy road and the speedometer would/should swing up but you would be creeping or not moving as fast as the speed indicated, but the traction is fine, and the speedo just indicates the actual speed traveling while my foot is in it and it should really be spinning its wheels. It does get up to speed but is lagging…

Ran poorly when i cold started it after the 5 hours at work but made it home with all the same conditions. It smoothed out some as it warmed up

When I am parked the idle seems to hunt in a high low high scenario that repeats itself every few seconds, No codes stored, no CEL, no codes while idling, or under forced load IE running in gear with foot on brake and loading engine. scanned it when i got home.

All fluids are up, the trans fluid is just above the add mark but clean. I did a water pump, timing belt and tensioner a couple months ago…the pump was a weeper, hated that job. New air filter and plugs,cap, rotor wires installed then, say early NOV.Cleaned the throttle body then as well. No fluids on the ground since then. all wires are properly inserted in the cap. I had a cyl misfire code just after the new wires were installed 2 months ago cyls 1,3,5 but that was the cap end terminals were just slightly loose. a push back on and no codes no miss after that, till yesterday? full tank of gas two days ago and have about 100 kmh/60 miles on that tank.

all of these conditions are slight, like they are definitely noticeable but none are extremely worse. I had a trip planned to pick up some Christmas gifts I had shipped to Pembina ND just across the Canada / US border tomorrow, 4 hours round trip but this has put the kibosh on that, I’ll have my 5 year old son with me and don;t want a break down on any road with him if I can help it.

I’m thinking sensor? I can snap the throttle when it is running in park and it revs but seems like its not as crisp. I know my dad had trans issues with his 89 GC 3.0L but other than this water pump of late , this thing has treated us very very well. I’m not leaning towards trans, especially since the idle seems wonky/erratic.
Previously it wouldn’t snap your neck ,but it would downshift and pass or get up and go when you asked, now, not so much…

UPDATE …THIS MORNING I took it out for a small drive this morning after the school bus came, ran really rough on the cold start, didn’t stall but was a RUH - RUH - RUH labored running before engine warmed up. Down the road waiting at the bus stop it stall once while waiting for the bus to arrive. started right back up no issue.

still have a rough ruh ruh ruh ruh kind of sensation like one beat per second timing, very strong when cold, smoothed out to about 90% gone when warmed up but still noticeable. can get it to spin the tires on the icy roads but doesn’t seem to accept the acceleration applied to the pedal like it should. i have my foot in it it should either downshift and charge or spin and swing the speedo up… but if i did get the wheels spinning
they would just climb up slower than normal like 30 mph 40 kmh and climbing when it should be climbing and reading the wheelspin at a much faster rate like 40-50 mph and . no codes active or stored … my OBD tool has an emission " guage " on it like
a stoplight, green yellow and red. it does work when i had the misfire after the new wires ( see water pump re&re listed above ) the light was yellow, I refit the wires in the cap and cleared the miss fire code and it read green. figured that tidbit
was worth mentioning.

basically it feels like the engine is being held back, like a heavy , heavy spring would on a carburated vehicle. it still works but has a wet blanket on it.

also will mention in the past week or two I’d say i may have noticed a slightly lower idle speed when stopped at a light but like i mentioned the heater fan and lights are
getting used more often at higher frequency as it has been cold and the sun sets at about 4 pm this time of year

temp here this morning -25c / -13f

ANY suggestions or help would be more than appreciated.

Derek

2

I would check for fuel pressure and vacuum leaks. The IAC maybe dirty and cause a rough idle. I take it the not CEL on still. The other problem where it seems to have high rpm and no go, sounds like a tranny problem. Dodge is famous for those.

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checked yesterday, vacuum looked good 18 - 19 inches, it followed the idle up and down. We ran a timing light on all plugs all have spark in the high tension wires, but interestingly on the coil wire, just before the engine has a three second “ruh ruh ruh” session during and rough idle patch then smoothing out ( this rough idle is all intermittent as well , it will smooth some ), the coil wire looses signal a split second before each “ruh”…so you get a split second of light going out and coming back on just before each “ruh” so the rough idle is “accentuated” by this loss of voltage in the dist to coil high tension wire when you have the timing light hooked up and are watching it, which would lead me to believe a cam sensor? Still no codes, which I find odd. I am always half expecting some codes from these newer vehicles…my 74 Monaco was a cake walk.

4

-20F??

Do you have an engine temp gage, or just an idiot light? It sounds to me like the engine is struggling to try to warm up and to stay at operating temperature. At -20F, you may need to put a sheet of corrugated cardboard in front of the radiator. -20F can dissipate heat faster than many engines can generate it.

In addition, allow me to add my own experience from My years in North Dakota. When the car sat in temperatures like that, I always used an engine heater overnight. Even then, the car would feel like it was dragging an anchor. The manual tranny and differential fluid was so thick that it felt like dragging an oar through wet concrete mix. It’s possible that the -20F is the culprit rather than a part malfunction.

5

I had a dodge 3.5 tb that jumped 1-2 teeth after 1 yr. no codes. I only was checking cuz wp started to leak. Crappy new parts. Did tb jump cuz of coolant leak?

6

@Cavell Could you please use full words so the person asking questions will fully understand what you are trying to say?

7

It sounds like the transaxle is in “limp home” mode. I believe by 1999, all 3.0L vans had the 41TE transaxle. When the powertrain control module detects a fault, it disables all electronically-controlled gear ratios, leaving you with 2nd and reverse. One frequent cause of this is a problem with the input and/or output sensors, or the solenoid pack.

8

It sounds like OP knows a thing or two about cars. Many of the people asking questions don’t know what a timing light and vacuum gauge are, let alone know how to use them

9

A friends Dodge truck goes into limp mode due to a cam position sensor that is intermittent. Turn off the key and most of the time it will run fine and no codes or light.

10

OK, thanks for all the posters and thoughts here. A few things to update. Condition is still active and fluctuating as before. when i say fluctuating I mean it still has intermittent missing, and the occasional stall when stopped in gear.

But we have a few variants to take out of the realm. swapped the coil and cam sensor out with used components,one changed at a time, no difference, condition still active. tested TPS throttle position sensor, no faults found. I have a new crank sensor coming from a buddy at the parts store, and a replacement PCM power control module / computer that my dad bought for it years ago when he owned it. so we know the tps/ cam sensor and coil are not the fault. soon to know if the pcm or crank sensor are to blame. failing that. I’m stumped. I’m thinking the Chrysler dealer hopefully may have a tool to scan it and see something…which brings up another point.

I have scanned the van with two OBD II scanners, mine that reads stores and erases codes but does not show live mapping or data, and another i borrowed from a co-worker that does, and i will say the most interesting thing i saw on it was the timing. when running , parked the idle shows anywhere from 12-15 degrees and can , for a split, split second sweep anywhere from -4 to 20 degrees, etc. I am assuming the timing at idle in park should remain fairly static.

what i have now is anywhere from a slightly to fairly rough idle while parked, an intermittent miss while driving that , dependent on the speed, could feel like a slight hiccup or a noticeable surge. and at the top end, 80 kmh-100 km h / 50-65 mph , if you accelerate as if to pass, it feels sluggish while trying to drop out of the passing gear into the final overdrive. That said, the trans is not in limp mode, all fwd and reverse gears are present.

i dunno.