hesitation/spark issue?

[Ooomph]

Last two times I've driven the car ('03 w/25k miles) I've noticed a considerable hesitation when releasing the clutch from a dead-stop, at speed it drive's okay but still seems like it's slower than normal. Engine sounds like it's might be missing on the driver's side, also noticing an occasional (very light) backfire pop in the driver's side exhaust & a very rich smell after it has fully warmed up.

I've checked all of the plug wires and they're fine. I'm leaning towards a coil pack or spark-plug maybe? No codes. Any ideas?

To me, it seems as if a plug isn't firing and I'm passing gas D lol) thru my exhaust. The car was recently in the shop for a broken header bolt on the same side, could it be possible that the exhaust leak fouled a plug? I have not removed any plugs yet.

mods:
Belanger headers, hi-flow cats, crossover delete, K&N intake, DC computer mod. Be advised that I'm running with cats but no O2 sensor wires. Long story short, the computer has been hardwired to believe that the O2 sensors are good as a result of several o2 sensor wire/header burn-thru's.

Being that it does have 25k miles I may go ahead and replace all of the plugs anyway. Does anyone recommend any specific brand or just go with another set of stockers? And at what gap?

 

[DMan]

Well here's a coincidence, I just noticed I have the exact same thing happening.

I did the mods in my sig, minus the plugs, and the car was running great, drove it for a couple hundred miles. I put in the plugs and only drove it a few miles & it seemed OK.

I took it to dyno & noticed it popping & thought I felt a hesitation but didn't stop me. After dyno (which seemed a bit low), on the drive home I had the symptoms you describe above; popping, a muffled type backfire on accel twice, hesitation especially in low rpm, dramatic in 3rd & 4th gear, etc. I checked my wires all are snug. I was thinking of throwing my stock plugs back in to see if it's the plugs I put in. Let's see if anybody has a suggestion.

 

[ILLSMOQ]

Last year I was getting a form of hesitation at low RPM, just tipping into the throttle. It was doing it for a couple weeks......then it never happend again.

 

[Ooomph]

it sounds like bad gas but my problem didn't start until 70 miles into the tank. maybe I should top it off from a different station and add some octane boost to see if it resolves itself. thanks for the input gents

 

[GR8_ASP]

I have had the issue as well. Almost exactly as described except with the passenger side (also with crossover delete). Only happens at very low rpm and low throttle. Sounds like 5 cylinders only for a few seconds. Weird.

 

[wormdoggy]

Ditto same here.
I have the belanger headers, high flow cats and delete cross over. I'm getting mine tuned next week.
I did, however, change secondary 02 sensors and put o2 simms on. The wiring kept getting burnt due to the position under the shield.

I notice the hesitation when the car is warming up. Once warmed up and kept in the 3-4 k RPM range the car runs fine. A friend of mine told me that it makes sense since the 02 sensors need to get hot to provide accurate readings or something along that line. Something about a loop. I'm seeing him next week and will post the results.

Patrick


Patrick

 

[GR8_ASP]

ok I have O2 simms as well. I do not think they could affect it but th eprimary O2 sensors could. Note I failed the right bank O2 sensor once before (heater circuit failed). It ran strange during warm-up for a while before I got th eMIL. I will monitor the O2 readings during warm-up and see what happens.

 

[Racer Robbie]

Guys,

I would check your O2 Simms wiring to be sure they have not been burnt.
Check all the spark plug wires with an ohm meter.
Change out the plugs, I have seen brand new plugs that are defective.
E10 fuel causes all kinds of headaches. I run octane booster all the time.

Robbie

 

[Ooomph]

okay gents, I'm feeling like an idiot what's the secret to pulling the plugs?


seems I cant get the (craftsman 5/8" spark-plug specific w/the rubber-boot inside) socket on all the way due to the individual plug shields. do they have to come out prior to pulling the plugs? and if so, are they just compression fitted? do i just squeeze the sides together a little and slide them out? just wanted to check before I put a take a set of channel-locks to them .


Any help or guidance would be greatly appreciated!

 

[Racer Robbie]

Ooomph,

The spark plug socket which should be a 3/8" drive 5/8" wobble spark plug socket. There is no need for the rubber insert in the socket. You can use a small length of hose to push over the spark plug tip to remove them and also to start the threads on the new plugs. The shields tend to move around from the heat caused by the exhaust manifold and can be pried away from the plug with a screwdriver to give the socket clearance.

Robbie

 

[DMan]

Well it's fixed. I don't kon exactly what was wrong, but I went & picked up a set of MOPAR plugs, pulled the XPs and installed the MOPARs. Test drive thru heat cycle, oh, and it's hot here now, whew, thank goodness for my cool Corsa, anyway - running smooth as silk, idles like a purr, no hesitiation on shifting, low rpm, etc etc. So, now I have a $55 set of XPs on the shelf, they looked awfully black for about 200 mis of driving. But I'm happy, back to cruizin.

PS- thanks Ooomph on the gap setting for the MOPARs.

 

[DMan]

Ooomph, just saw your ?

When I did mine the 1st time I said it was easier changing my exhaust then doing my plugs, but after the 1st time it's cake.

In case you haven't done it yet. I used a sets of pliers to grap the heat shields and wiggle them out, pull the cap, change the plug, then thread the plug wire, put the cap on so I could feel I had good contact and then used the pliers to wiggle the shields back on. I used a spark plug socket from Sears for a perfect fit, I took the plug with me to ensure it was perfect, and I found the rubber insert to be a godsend, no worries of dropping a plug down in the abyss of the skid plat area, etc.

Goodluck, and your not an idiot ... um, cause then I'd be one too cause I had the same prob the 1st time. lol

 

[Racer Robbie]

Well it's fixed. I don't kon exactly what was wrong, but I went & picked up a set of MOPAR plugs, pulled the XPs and installed the MOPARs. Test drive thru heat cycle, oh, and it's hot here now, whew, thank goodness for my cool Corsa, anyway - running smooth as silk, idles like a purr, no hesitiation on shifting, low rpm, etc etc. So, now I have a $55 set of XPs on the shelf, they looked awfully black for about 200 mis of driving. But I'm happy, back to cruizin.

PS- thanks Ooomph on the gap setting for the MOPARs.

Dman,

Were you running XP985 Plugs? Did you re gap them, if so you are not supposed to re gap an iridium plug, and did you torque them. We have installed over 500 of these Autolite plugs in non blown vipers and have never had a problem or a black plug. Perhaps the spark plug wires were not on all the way. Please give me your feedback as I am very interested what caused your problem. I have over 8000 miles on the set in our test car. By the way the XP985 plugs are warrantied, you can return them to Autolite.

Robbie

 

[GR8_ASP]

Over 500! You must be the Number 1 viper service location for plugs.

My hesitation is indeed the same cause as last year. An O2 sensor heater starting to fail, causing a slow response when cold. Most noticeable immediately after it goes to closed loop operation. Once the sensors are hot there is no issue. Have other Paxton owners had O2 sensor failures? This is my second one. Same bank also.

 

[DMan]

Robbie,

In taking out the xp985's I was looking for some bone head thing I had done on the install; the plug wires were all snug, the plugs all felt good and right torque, I check the tips in case I had damaged one on install, etc. I use iridium plugs in my dirt bikes so I'm used to them, didn't use any guage them, etc.

I only went for a 20 min drive & all felt good. I'll try to get a real drive in tomorrow to really test it out to make sure all's good. I put the MOPARs in thinking it might be trouble shooting move & if the persists & I take it to the dealer I'm sure they'd say put stock plugs in first, so here I am. Seems the probability of it being the XPs would be small, but right now I don't, a real test drive and we'll see.

 

[Racer Robbie]

Dman, Putting in the factory plugs is the right move if you are taking the car to the dealer to be diagnosed. Please keep me posted.

Thanks,

Robbie

 

[wormdoggy]

Just wanted to add that I did some work on the car this weekend. Spent about 4 hours installing 8.5 mm MSD wiring / boots and new plugs. I just added the plugs since I figured what the hell since I had the intake manifold off. The plugs were champion new stock plugs.

Well the hesitation / gargle problem I had is completely gone. There is a tremendous improvement in acceleration. The car is running impressivley with crisp response on acceleration. If I new this would be the case, I would have done this a long time ago.

One of the things we found when changing the plugs was that the plug gaps specs were way off. Don't know why this would be and I don;t know how important it is , but I just thought it would be worth mentioning. Also the wiring is just nite and day to the stock ones. Would highly recommend this modification.

Patrick

 

[Racer Robbie]

Over 500! You must be the Number 1 viper service location for plugs.

We have sold a ton of these as most Jeeps with straight 6 cylinder engines use the same plugs. Also have installed these plugs in motorcycles and boat engines.

I am going to try the new Bosch 4508 Iridium Fusion plugs if I can ever find anyone who as them in stock.

Robbie