Small Engine Jerk, help!

[Contrakt]

Hey guys. I have quite a confusing issue with my car, and am brand new to this forum. First car forum I've ever been a member of--here it goes.

I have a 1998 dodge Intrepid ES with the 3.2liter V6 with 124,000 miles on it. I just bought it from my local dealer a week ago for $3,600.

Unfortunately I have no receipts from past work on the car, so I have NO idea what's been replaced and what hasn't.

Here's the issue with the car: At highway speeds (Usually 50-70mph) it has a small downward feeling jerk. Not a pull, not a lunge, not a lurch, a JERK. It happens ever 15-30 seconds. It never does it in harmony or consecutively, always at random times and never evenly spaced out. It's a small jerk, doesn't feel like anything crazy is happening; just a small jerk that you can feel coming from the engine. And when I mean small, I mean your average-joe wouldn't even notice it. You have to turn the music all the way down, and really steady out, and........ *Jerk* THERE IT IS!

I can't feel it in the peddle (Gas or brake), I can't feel it in the steering wheel, and the RPMs and speed stay the same, nothing visibly is affected at all. Just an engine jerk. Like I said, very confusing! If anyone could let me know their input I would appreciate it. Only thing I can come up with is possibly the timing belt? My car does have the symptoms of a worn timing belt (Runs hot, visible exhaust, small engine vibration at idle.)

Let me know! Thanks!

Contrakt

[jamesslcx]

Contrakt, are you sure it's not a slight miss? Have you checked the plugs and related stuff yet? And those symptoms you mentioned could be maint. related as well.

[Contrakt]

Originally Posted by jamesslcx

Contrakt, are you sure it's not a slight miss? Have you checked the plugs and related stuff yet? And those symptoms you mentioned could be maint. related as well.

Just a week ago I replaced all spark plugs with the most expensive ones I could find at O'reilly Auto. Still doing it, but not nearly as much. This car has the head unit over the plugs, and those are replaceable as well.

Thinking about trying that out. But since I replaced the plugs I THINK it's doing it less.

Also, wouldn't you think a miss would set off a code of some sort? Even a check-engine light? Nothing of the sort is happening. No codes or lights.

Contrakt

[tempfixit]

Originally Posted by Contrakt

Just a week ago I replaced all spark plugs with the most expensive ones I could find at O'reilly Auto. Still doing it, but not nearly as much. This car has the head unit over the plugs, and those are replaceable as well.

Thinking about trying that out. But since I replaced the plugs I THINK it's doing it less.

Also, wouldn't you think a miss would set off a code of some sort? Even a check-engine light? Nothing of the sort is happening. No codes or lights.

Contrakt

Have you checked for any pending codes even tho you do not have a check engine light on???

[jamesslcx]

Possibly a coil problem also expand a little more on the overheating you mentioned.

[jamesslcx]

Oh yes, it seems like on some vehicles a drivability problem doesn't set of a check engine light 100 per-cent of the time.

[Contrakt]

Originally Posted by jamesslcx

Possibly a coil problem also expand a little more on the overheating you mentioned.

Yeah it doesn't actually OVERHEAT but the engine is just physically really really hot after driving. I've owned 3 cars, all buicks with the 3800 in it. So I'm not used to a vehicle like this obviously, so is that just normal for this vehicle? The engine is physically so hot after driving I can barely open the hood. But according to the gauge it's cooled just fine.

[jamesslcx]

I went to Lowes or HD and bought an infrared thermometer and use it to check the temps on my vehicles, you never know when the gauge might be wrong. Aim it squeeze the trigger and almost instantly you get a temp, just be careful and don't get too close to the running engine. It sounds like it may be hot especially where you live. Do the cooling fans come on?

[Contrakt]

Originally Posted by jamesslcx

I went to Lowes or HD and bought an infrared thermometer and use it to check the temps on my vehicles, you never know when the gauge might be wrong. Aim it squeeze the trigger and almost instantly you get a temp, just be careful and don't get too close to the running engine. It sounds like it may be hot especially where you live. Do the cooling fans come on?

The cooling fans on this car (While at running temperature, not when just starting, obviously) are ALWAYS on. After just a moment of idling in the driveway they're always on.

[jamesslcx]

Contrakt, hmmm, maybe a faulty sensor. When the engine is warm the fans do not go off at all? Probably wouldn't hurt to have a cooling system flush and fill. How does the coolant look? Nice car though, they are priced very high in my area if you can find one. Very worth spending some money on if you have to.