Cmr0z28

O2's, burnt plug wire, fuel filter. Do all of these before you tackle the opti

transamdude95

Mine has the hesitation problem when cold, from when I start it til I shut her off. I stopped by Autozone on the way back from work today and bought a fuel filter. Since it's only $7 it won't hurt, and I can't remember the last time I did this, or if I even have done it since I bought the car... I'll try 02's next, how easy are those to replace? Simple from what it looks like.

1Qwik94Z

most likely a faulty O2 or plugs/wires. I had a small stutter around those RPM ranges..then it got gradually worse. Turned out my Opti was shot (94z non-vented). It kept stuttering more and more until I couldnt bare it..I lost over 50% of my power, atleast!
After that...I had a problem with my Catalytic Converter..it came off the welds its all aftermarket and I dont know why or how but it just did...didnt scrape anything
....Anyways, I drove it for a few days/week..and it started sputtering. Now this is after I just replaced my Opti and also the WaterPump after the Opti (within a week, since I had the front of the engine off). Since the Cat was off, I drove it like this for a while the car started sputtering again, really bad. I ended up garaging my car and driving my Pathfinder for weeks till I had the dough and time to fix it..after I figured it out. I replaced my coil, checked all my wires (no burns or breaks)...removed and cleaned my EGR valve and regulator, and figured it to be either my Opti again since I may have spilled coolant from the WaterPump when I changed the Thermostat. I was puzzled..well I finally took out all my plugs..1.3.5.7.2.4.6 and wait..when I took out 8..I found my problem! Since my Cat was off, there was a HUGE amount of exhaust build up on the plug and inside the wire for plug #8. I cleaned it all (in gasoline..free cleaning agent ) and regapped my plugs, checked all the wires..and POOF! My car ran great after that.
Sorry its kinda long..but before you go and replace the Opti, or even the O2 sensors which will still cost you more than you need, for now anyways, check all your plugs and wires. Most simple reason besides blaming it on the wonderful reputation of the Optispark. And dont worry, I thought plugs and wires were gonna be tough! I just took mine out, regapped them all in less than 20 minutes yesterday..ALL 8! I found a neat way of sitting in the engine compartment where I can angle my arms just right. Only thing is I stick a rag near the RH side (passenger) exhaust manifold..cause I get the manifold part numbers permanantly marked into my arms if I dont
Again, sorry its so long, but remember its probobly nothing serious. Check first..and worst case scenario, if it is your Opti, Just yesterday someone mentioned a FULL OptiSpark from Autozone for $130!!! Thats amazing with a lifetime warrenty..(a discusion on the reliablity and quality is not needed, thats for a different thread guys ) Just an FYI..good luck!

EaC95Z28

thanks for the info man. i dont think its my plugs and wires but it very well might be. there were replaced about a year and half ago only about 15k miles ago. i would say they are fine the car runs great and i figured if it was misfiring cause of one of the plug or plugs it would be at least at WOT but its not. dont think my cat is clogged, anyway to check that? it is the stock cat i know for sure. i was planning on putting in a carsound high flow cat. hope its not my optispark at all. how did you change your plugs and wires or check them that fast? i dont have headers so i still have the stock manifolds. one more thing. could it be the TPS sensor on the throttle body? a mechanic i asked said it could very well be the TPS have carbon on it and when im just crusiing or accelerating with light throttle it could be sensing a bad spot on the TPS sensor causing it to throw off the amount of throttle im really giving the car, thus causing the hesitation/sputter. no way to check an o2 right? how hard is it to replace it? i know theres the one thats on the y-pipe on the passenger side but i cant recall seeing another on the opposite side. im pretty sure theres 2 o2 sensors on our cars. thanks again let me know guys. i hopefully will be getting my fuel filter and tps sensor tom to replace. hope it solves my problem. i miss my car!

transamdude95

I replaced my fuel filter yesterday and smelled like gas the rest of the day... .... but it didn't fix the problem. Right after that, i decided to pull a few plug wires off to see if they looked fine. That turned out to be a PITA because they were tough as hell to pull off. I tried pulling/twisting off the #7 plug wire and the bastard turned the whole spark plug I figured the spark plug 'came loose' somehow and when i finally got the wire off I tightened it down. I put the wire back on in total anticipation to see if my problem had been fixed, but no.... Didn't do a damn thing. I'll check my #8 plug when I find time, hopefully tomorrow. And I bought Seafoam to do some deep cleaning Anybody else have some new info?

1Qwik94Z

well EaC...the secret of my spark plugs is simple, IF you have small enough arms (Im muscular/athletic but only 150lbs). First off, I change all four plugs on the passenger side from the top of the engine. Real EZ. I also change the first three from front (plug 1) to the third one (plug 5) from the top. The only plug Im pretty sure you HAVE TO change from underneath, is plug #7 (Driver side, rear most plug).
What I do is...for the passenger side..I have a patio chair (just a plastic chair) that I dont care about getting dirt on from my shoes lol...(even though my garage is VERY tidy )...right at the NOSE of my car. I lay on top of the intake manifold and slowly maneuver my left arm down and back towards the #8 plug. I usually lay a shop rag on the exhaust manifold because I get part numbers imprinted into my arm for a few hours if I dont # 6 (3rd back) is alittle easier, but I still lay on top. #4 and #2 Im just sitting in my engine bay. I just sit in my engine bay also (my bum on the intake and my feet on the radiator shroud) for plugs #1-#5. Then like I said, #7 I use my 'creeper' and quickly change out/clean it. None of them are hard to do. Id say from a scale of 1-10..1 being you can reach in and do it from the ground..and 10 being taking all kinds of crap out and hurting yourself in the process...1-7 are a 2-3 and #8 is a 4. Its only inconvenient really..not hard.
Long enough already? lol...

As far as the Fuel Filter..I just changed mine out like 30 minutes ago. When I pulled my old one out (it was only a few months old..maybe 5), I couldnt feel ANY air when I blew through it. When I blew through the new one, I felt a lot of air through it. So when my #8 plug was fouled from exhaust crud, and my fuel filter was clogged/fouled..I thought for sure it would fix it. I now have a much better respons..but still hesitation during slight acceleration and WOT. Im pretty sure the fuel filter would be a constant (light acceleration/WOT) problem. If its simply not getting the sufficient fuel at one stage..I cant see how it will get 100% fuel at any stage if its clogged. Just make sure if you take it out to check it, you 'crimp' both ends of the fuel line..I forgot and only crimped the rear part..unbolted the bolt and there was a lot of pressure in the line from the filter to the engine..that sprayed out on my face and hands. Luckily I always have rags and plastic buckets, along with saftey glasses whenever Im under the car.
There is another O2 sensor on the driver side if you look hard enough, its up ABOVE or BEFORE the Ypipe connects to the manifolds (pretty sure..or opposite..whatever your passenger side is..driver is opposite) Im not quite sure what symptoms a bad O2 would have..I may have that problem..I just dont know HOW to check that. And i dont have a scanner to see if its reading right. Between that and the Opti, I honestly dont know what else could cause a hesitation. Just a recap..what all have you checked that it could be?
-Fuel Filter (pressure)
-Plugs/Wires
-Optical Spark Distributor
-O2 Sensors
-Coil/Ignition Module (little thing bolted above the Coil)
-Injectors
-Thats about all I can think of for now..Good luck and let us know if you figure anything out. Sorry its so long, I have time on my hands and nothing to do right now

EaC95Z28

hey man thanks for the reply. i went and talked to a mechanic i know at the dealership and he said that it is most likely my plugs AND wires so i will be doing this soon. how hard are the wires? you make it sound like the plugs are pretty easy now but what about the wires? anything special i have to remove? i know i have to route them right so they wont burn up but i willl hopefully be doing the plugs and wires soon. im sure it will take ma long time. i will alway be changing my fuel filter out soon too hopefully when i do it all together. i still havent really checked for it yet but i am going to check for arcing and the weep hole on the water pump/optispark. thats what my mechanic told me to do. so i will hopefully be doing this soon. im currently not driving my car right now and it really sucks and i miss my car. thanks alot and ill keep in touch. u have been a great help.

TobyZ28

I have had the exact symptoms you are describing. Light throttle, more noticable going around 50-60mph in my A4. I've been trying to fix this problem for ages. Ive replaced the O2's (bosches though) which didnt fix it. Coil, Plugs, Wires, transmission was rebuilt, engine was rebuilt too, EGR, MAP etc etc. Still havent fixed it to this day. I've also cleaned up the MAF many many times.
I have NOT replaced the CAT, Opti or the Injectors. I have also not replaced the Bosch O2s I got not long ago with the better AC Delco ones.
Right now my guess is on the Injectors, then I'll try the O2 sensors (although in freescan they seem to be operating ok).

I hope you fix this problem, if you do please please send me a PM/Email or anything. I'll be sure to check back on this thread anyhow

BackNBlack

i found another long thread about this (15 plus pages) and some people fixed it with relocating the Ignition Control Module off of the head and some fixed it by replacing the Map sensor? (The square one on the to of the intake) or cleaning it. Nobody ever put up a definative answer, not even the experts like Mindgame or Shoebox, so it seems throwing parts and $$ at it is the only way, and everyone's fix is different.

EaC95Z28

yea i will keep in touch and let you know but i dont want to have to go throught hte headaches, money and time like you have to replace all that stuff and still not fix the problem. my mechanic is pretty certain on the plugs and wires but im not sure. i will be checking for arcing maybe this weekend. i have really no time, it is my daily driver and i am not driving it now. im a full time student in college and i work part time quite abit on the weekends and some on the week so i dont even know when i can make the time to check it out and fix it. im pretty upset with it. seems like i fix one thing then another thing pops up.

TobyZ28

Mines a daily too and i work full time and go to school at night as well. I hope your mechnic can fix this... What i have noticed is that this "problem" is actually several different problems when you read other posts about it. Some people have the low rpm stumble when flooring it, some have it when feathering it in all rpm from 1500-2500, while others only have it happen when feathering light throttle at certain speeds (usually A4 guys like me). Then there are even people who have it fluttering all over the place but just decide to post their fix anyways. If your hesitation is bad enough it probably is ignition related. Mine is so hard to feel unless your going just the right speed (and the plugs have been replaced 2x on it now without much change). Hopefully yours is just plugs wires. Dont cheap out on the spark plugs, get the OEM ones or some of those NGK(?) ones people recommend on this board.

Kurt Crosbie

Wouldnt you get an SES if the o2 sensors were bad?

EaC95Z28

yep ur thoughts are just like mine. some peoples hesitations are major while some are just minor and at specific rpms. i have an m6. if urs is hard to feel i wouldnt worry bout it then. but when u can notiice it all the time or something that bothers you then it would be something truly wrong. but it sounds like ur car is fine. yep i hopefully will change my plugs and wires soon. i hope it wont take me too long. is there anything special i have to remove to change the wires and plugs? i know i have to route the wires right but can i mount them with everything still bolted to the engine and so forth? i will be probably purchaseing the ngk tr 55 plugs it hink is what they are the ones that are good. the oem ones are on right now the 100k platinums but i guess they are bad. i know taylor makes 8.5mm wires and msd also. will those fit in the stock routing locations? or will i have to stay with stock ones. i want to upgrades some as i am doing this too.

TobyZ28

Wiring can all be done from under without removing anything. Things to keep in mind:

-Use a bit of di-electric grease on the BOOT (not the connectors).
-Take your time wiring. Think about how they will move while driving too.
-Be gentle when threading in plugs so you don't strip the block.
-Do one wire at a time while taking out an old wire. Prevents you accidentally hooking up the wrong cylinder.

When you route the wires it will be fairly clear and easy to see if theyre going to hit a header, remeber to just take your time doing it and check each one over from end to end.

Although mines only at certain speeds, its a speed i drive a lot and it is quite noticable to me Drives me nuts. The last time i did the plugs it seemed to have helped a lot but it came back very soon after...

EaC95Z28

thanks for letting me know about the wires, good information. yea even though mine is at certains epeds like urs i drive at that speed normally cruising and so forht so it is annoying and always sputtering/hesitating. so u did ur plugs/wires and it still came back??? hmm. i dont want it to come back haha i hope it wont. thanks