stumbling to my wits end

[Sexymeatball]

alright, im done searching the forum for an answer and havent fixed it, so now im posting...sigh...within the past few weeks my car has developed a stumbling problem. It bogs down ******** when i engage the drivetrain from a complete stop, but doesnt have this problem from a roll, even a very slight one. In addition, im having an ever worsening stumbling around 2k-3k (rpm). it doesnt seem to do this in the higher rpm's or maybe i just dont notice. I replaced the TPS about a month ago, cleaned the MAF and ACT today, and checked the DIS or wires for bad connections. The wires are stock (car has 137k as of today) but 10k miles ago the resistance on them was fine. Plugs are fine and there is no oil in the wells. Fuel filter was replaced about 1k miles ago. Fuel pressure was fine when i checked it 2 months ago. no vaccum leaks that i know of. I havent pulled the codes yet cause its raining right now, so im doing that tomorrow. My first thoughts are that the wires are finally starting to go, but i dont want to replace them if i dont have to. lets see what else...02 sensors were replaced 5k miles ago...nothign else i can think of that might effect this problem right now. Someone please steer me in the right direction. Thanks

 

[filc03]

Not that this is of any help, but your problem sounds pretty similar to mine. See my thread around the top here. Resetting my idle helped a little, but I'm still not there yet. You've replaced more than I have though..hmm. I'll be watchin this one pretty close

 

[masho95]

alright, im done searching the forum for an answer and havent fixed it, so now im posting...sigh...within the past few weeks my car has developed a stumbling problem. It bogs down ******** when i engage the drivetrain from a complete stop, but doesnt have this problem from a roll, even a very slight one. In addition, im having an ever worsening stumbling around 2k-3k (rpm). it doesnt seem to do this in the higher rpm's or maybe i just dont notice. I replaced the TPS about a month ago, cleaned the MAF and ACT today, and checked the DIS or wires for bad connections. The wires are stock (car has 137k as of today) but 10k miles ago the resistance on them was fine. Plugs are fine and there is no oil in the wells. Fuel filter was replaced about 1k miles ago. Fuel pressure was fine when i checked it 2 months ago. no vaccum leaks that i know of. I havent pulled the codes yet cause its raining right now, so im doing that tomorrow. My first thoughts are that the wires are finally starting to go, but i dont want to replace them if i dont have to. lets see what else...02 sensors were replaced 5k miles ago...nothign else i can think of that might effect this problem right now. Someone please steer me in the right direction. Thanks

Do you notice it stumbling more when the engine is cold? Or does it seems to happen at any time? I'd definitely change out those wires to start with. Just because of the age of them. I can't believe that they lasted 137K miles! Even with perfect resistance I believe the possibilty of hairline cracks causing a misfire is possible. Although it wouldn't make sense on why it doesn't do it at a roll. I've got a similar problem with my SHO and it BOGS bad from a stop but only when the engine is dead cold. And I previously had the 2K-3K stumble. I replaced the plugs and wires and that's about it and the stumble seems to be gone. But the cold engine bog is as bad as ever. Changed out the MAF today and I'll see how it does when cold tomorrow morning. I've tried cleaning the MAF too, but I want to see how it does on a completely different MAF. As soon as it warms up it won't bog though so it's weird. I'm wondering if on my car it's something to do with the closed loop mode that the car runs when cold... Oh well I'll see where I'm at tomorrow. Good luck finding your problem too!

 

[Dr. Tweak]

Did you check the codes? There's a guide on the SHOPP website (link in my sig)

 

[Sexymeatball]

no it stumbles all the time. And now that i think more of it, it does stumble off of a roll, just not nearly as much or as pronounced. I think i will replace the wires considering the AC delcos are 33 bucks at rockauto well i'll update when i get the codes tomorrow.

 

[Sexymeatball]

and now, for the moment you've all been waiting for! Codes! alrighty...when i first ran the tests i didnt clear the codes first and got a little scared by a 159 (MAF is/was out of range) among others but that went away after i cleared the codes. Here we go: KOEO: 111...thats good. KOER: 412, 116, 225. I know what these mean, but i have no clue what to do with them. I will be searching the forum, but if someone knows or has a thought, please post, thanks.

 

[AutoSHO]

Make sure when you replace the plug wires, you replace the plugs again at the same time. I fought a problem like this (misfiring, especially from a sto and at low rpms) and it was a bad plug wire - but it was leaving a carbon track on the plug, so replacing just the wires had no effect.

 

[Sexymeatball]

the plugs are fairly new though. changed em out when i first did up the car. is that really necessary?

 

[AutoSHO]

Mine were < 3k old, and still caused a lot of stumbling and misfires.

 

[Sexymeatball]

point noted then

 

[Sexymeatball]

at the moment im resetting the idle and then gonna rerun the codes...ill update then

 

[Sexymeatball]

well, all the previous codes are gone, but now im getting a 167, which makes absolutely no sense because i just changed out the TPS recently, and i would think that i would think that if its a bad TPS, it would have shown up previously. as for the stumbling, i would like someone to tell me that the wires (and plugs i guess) are the most likely suspect so i can justify spending money (i go to college and as such, am very poor, lol)

 

[Sexymeatball]

for my 4th post in a row things are starting (finally) to add up in my end. the engine has sounded rough for awhile when i rev it (almost like mini backfires). I just never put two and two together. In addition, i read somewhere on this forum that bad plugs can be bad for your cats. Well, i replaced the y-pipe last august but have been unable to get rid of a pungent sulfur odor which normally points to bad cats. This last one may be a stretch but it makes sense to me.

 

[Sexymeatball]

Solved! Preliminary driving upon changing the the plugs and wires (AC Delco wires and motorcraft finewire plugs) reveals the my stumbling problem and bogging down issue are gone. Not to mention i havent yet smelled the sulfur odor which has been plaguing me as of late. I'll update if anything changes. Thanks for everyones help.

 

[sdpatt]

I'm sorry that I did not see this topic sooner. A misfire without a telltale EEC code is usually caused by leaking plug wires or incorrect or damaged spark plugs. I hope those AC Delco wires hold up okay. I have tried some lesser priced wires only to return to the Motorcraft parts. Good fix.

A resistance test will not reveal the main cause of the wire faults: spark leaks through the damaged insulator. You would need to performa what is commonly referred to as a megger or meg-ohm test. This is where a high voltage is applied to the conductor to determine if there is a fault in the insulation.

We used to do these at the nuclear power plant to check high voltage power wires. The only problem is that if the test fails, it can be quite a destructive result. This is not practical for something as relatively inexpensive as spark plug wires. At 137,000 miles, those OEM plug wires had been asking for a replacement for quite a while.

 

[shoteen95]

saw this thread and it caught my eye. Went to the girlfriends house today, after about a 15 minutes drive on the freeway we went out to dinner about 20 minutes after getting to her house. Started the car back up and it idled pretty low and stumbled, blipped the throttle up to about 2K and it fell down to about 1600RPM (pretty high) until i dropped it into gear, ran fine on the road...so far just a one time thing.