Stuttering missing and stopping

[Lemay88]

Bonjour again Viper owners,

Again some question regarding my beloved stock (k&n filters and borla catback exhaust)97 Viper R/T with 94000km
I’m gonna try to keep it short.
My Viper has been behaving strange since last summer. The problem mostly happens after going through stop and go city driving.
Problem is the Viper starts acting up with stuttering, missing fire and sometimes the car even stops....again after doing some stop and go city driving. I tried getting it on video to help you guys diagnose what is happening but so far, I didn’t have the car do it and having someone in the car with me to record it.
While doing the stop and go trafic, idle and temperature is fine. It’s when I’m back to slow cruising speed that the action begins.
When it happens, I depress the clutch and let the car “catch its breath” and sometimes it needs some gas pedal action to help it.
So, my first thought was it is battery related, so I changed my battery this spring thinking it would solve the problem, but it didn’t.
I have a permanent voltmeter in the car and it reads 13.6 when the car is running.
I think I still have the original spark plugs and wires but not really sure, how can it be verified??
Maybe this could help you also, I drove about 100km with driver side O2 sensor problem that I think overheated my cat.
I really hope to find the problem because the stuttering and stopping is scary when it happens suddenly.

Thanks again for you help

Ben

[dave6666]

Do the obvious things first. Which are mostly things that should have been done 15 years ago.

Plugs - use Gen 3, wires - Mopar are the best, clean or change the air filters, fuel filter. Sounds like you also need new primary O2 sensors - use Mopar NTK not aftermarket like Bosch.

Might want to inspect the cats. Reset adaptives. Check fuel pressure under load.

Also since it's likely behind schedule too, but unrelated to your issue, new belt and tensioner.

[Steve-Indy]

Lemay88, the OEM plugs that Dave mentioned for Gen III Vipers are Champion RC12ECC.... Gap .050

[dave6666]

0.050 gap? On my Gen 2 factory spec is 0.033 to 0.038. I use 0.035. What Gen uses 0.050?

[ViperSRT]

Gen 3, 4, 5 use 0.050 gap stock.

[plumcrazy]

also sounds like a cam sensor. at least thats how i described it when mine went out

or was it the crank sensor ? been too long for me to remember correctly

[Lemay88]

Thanks Guys,
Dave, when you write about the adaptives, it is the same thing you wrote when I changed my battery??
I will go with what is proposed and see if improves. (And hope it’s not the cam sensor as I hear they are no longer available.

[dave6666]

So when using the Gen 3 plug on a Gen 2 do you use the Gen 3 gap or the Gen 2 gap? Tuners?

[Lemay88]

Belt was changed last summer.
Could it be the alternator??
By the way, what gap is best for the rc12ecc??

[ticklechicken]

Do the obvious things first. Which are mostly things that should have been done 15 years ago.

Plugs - use Gen 3, wires - Mopar are the best, clean or change the air filters, fuel filter. Sounds like you also need new primary O2 sensors - use Mopar NTK not aftermarket like Bosch.

Might want to inspect the cats. Reset adaptives. Check fuel pressure under load.

Also since it's likely behind schedule too, but unrelated to your issue, new belt and tensioner.

Where do I get Mopar plug wires for my Gen 2? Part number?

[99RT10]

Where do I get Mopar plug wires for my Gen 2? Part number?

I have a set, PM me

[MH60M]

Did this get resolved? What was the fix? I get a weird miss and PO310, PO301, PO300, P0301 codes..... All related to misfire. Installed new wires, plugs, coils, and injectors one at a time to try and isolate the issue. Leakdown test might be my next move. ECU?

Thoughts?

[RT SERPENT]

Misfires could be a number of things as mentioned above. But if it actually just completely dies, you might look toward the crank position sensor
and the associated wiring harness that runs alongside the driver-side inner wheel-well.
Try wiggling the wire around when the car is running... that's how Mitch and I diagnosed mine. Easy fix, if that's the issue.

[Crimson135]

My 98 was throwing several misfire codes when I bought it. Ended up being a bad ECU. Check your wiring, sensors, etc. Unfortunately it seems like ECU failure isn't uncommon on vipers, or any 90's Dodge.

[MH60M]

Misfires could be a number of things as mentioned above. But if it actually just completely dies, you might look toward the crank position sensor
and the associated wiring harness that runs alongside the driver-side inner wheel-well.
Try wiggling the wire around when the car is running... that's how Mitch and I diagnosed mine. Easy fix, if that's the issue.

Thanks I'll try that!

My 98 was throwing several misfire codes when I bought it. Ended up being a bad ECU. Check your wiring, sensors, etc. Unfortunately it seems like ECU failure isn't uncommon on vipers, or any 90's Dodge.

Argh....sold my spare ECU to 99rt&GTS a few years back! I knew I should've kept it for troubleshooting.

Thanks for the replies!

[MH60M]

It never dies....or even feel like a misfire. I can’t get it to throw the codes at idle. Only when cruising.

Replaced ECU with a new updated one from Dodge. ......No change.

Well, car runs much better!....but I still have the misfire codes.

Thoughts?

[Lemay88]

Here my update.
With all the info from this forum and different search on the net I decided to go with easy and free test before spending money (yes, some of us are on a budget when it comes to pleasure car).
So, like I said, from reading different places on the net, I decided to investigate my voltage, battery and alternator. Changed the battery and it didn’t fix it then I was thinking to replace my alternator but came to think that my problem started after I had a coolant spill on the belt and alternator. I figured that it might have some effect on voltage and my problem. So I cleaned all the pulleys (the alernator was greasy at the touch before the clean) and was hoping it would be the solution...well, so far so good, my Viper is now running fine without any problem.
I hoping that was the problem

[Lalmeida617]

Lemay just cleaning the pulleys solved the issue? Is it possible the belt could have been routed wrong before you cleaned them?

[Lemay88]

I’m as surprised as you. I don’t think the belt was badly installed because when I cleaned the pulleys, I only removed the belt from the alternator pulley to give me some lose to clean the other pulleys and put it back after it was done.
Like I said, so far so good, no more sign of stuttering, missing and stopping...

[MH60M]

It never dies....or even feel like a misfire. I can’t get it to throw the codes at idle. Only when cruising.

Replaced ECU with a new updated one from Dodge. ......No change.

Well, car runs much better!....but I still have the misfire codes.

Thoughts?

Update: Re-Checked all inputs to the PCM that may alter the fuel/spark at cruising rpms/speed. I pulled the front bumper to double check the VAC/EVAP system and found the purge solenoid upside down...thus crossing the vac lines at the solenoid. This is probably the culprit since the PCM uses this data to adjust fuel and spark at cruising. BTW, I installed the solenoid as per the picture in the service manual....and the picture in the 2001 Viper service manual is wrong! The solenoid says "BOTTOM" on the bottom.