"Fishbite" Transmission not Transmission P0305

I've had the jerky thing people call "fishbite." I had it explained as it feels like a missfire, but it's caused by some seal in the Valve Body. When it happens, on hills, I can make it quit by shifting down from OD, or stepping on the throttle.

This time, I kept the throttle when it was doing it, to show a friend. I got a DTC, P0305 misfire cylinder 5.

The car runs fine all other times, except at certain times when it's in OD, up a hill. What would cause it to missfire, only under a limited situation? Seems like if something was wrong, it would either misfire or not.

One highway is 70mph and it never does it then. Only on the 60mph highway.

Chris.

If the engine is misfiring, it can feel like a transmission problem. If the transmission is not receiving a smooth flow of power from the engine, the transmission will not provide a smooth output, basically, junk in, junk out.

P0300 series DTC's are almost always caused by faults in the secondary ignition system: Spark plugs, spark plug wires and coil pack. How many miles since the last tune up using AC Delco plugs and good quality wires?

This time, I kept the throttle when it was doing it, to show a friend. I got a DTC, P0305 misfire cylinder 5.

The car runs fine all other times, except at certain times when it's in OD, up a hill. What would cause it to missfire, only under a limited situation? Seems like if something was wrong, it would either misfire or not.

One highway is 70mph and it never does it then. Only on the 60mph highway.
.

The car is running at a certain light load and you are getting a misfire on the spark plug wires or one of the plugs. I'd recommend new OEM quality wires and the AC Delco plugs recommended in the autoparts book. At the particular load and engine rpm you are getting a miss. If you open the throttle slightly more, it's gone. If you try the same load in 3rd gear at a slower car speed with the engine speed about the same, you probably won't get a particular mixture the same on those cylinders to evoke the misfire.

The transmission symptom you may be talking about is for the 4T65E transmissions where a valve is moved by hydraulic fluid and it changes the percent of lockup on the torque converter to adjust for load and rpms. If it has a sticking problem because of wear, the movement is uneven and the tach goes up and then back down in the period of a second or less as the slip in the torque converter clutch lockup is increased briefly. This feels like a miss. It usually occurs after the transmission is thoroughly heat soaked. For me it more noticeable on level light load roads. It occurs in 3rd and 4th.

about a year since I did a complete tune up. I used very good wires. Not sure the brand, but if I remember their Blue Wires at NAPA. Their the ones that people say they smell nice.

I did read over the years on this forum about using AC Delco Plugs. I wanted to use them but the mechanic I use, has done thousands of cars and in racing, done lots of tests. He recommended a different kind. Can't remember what he put in (I could guess and say NGK, but this is a guess). We have a massive snow storm right now, we're getting dumped on with snowball sized heavy snow. Will wait until morning to check what plugs for sure.

I have another problem I'm dealing with in another post. The last suggestion was change the coil pack. Maybe I'll try that. I'm not working so it will be hard to do it right now. Especially if it's not the problem. Used to have a knack for replacing stuff that turned out not to be the problem.

Another person I know in the automotive business, did tests on a whole bunch of different plugs. His finding where that there was no difference in performance. One difference was his test was done on very high performance engines.

As I'm writing this, I remember it did this on my last motor. This newer motor I put in has different coil packs. Wonder what would be the chance my old motor has a bad coil, and I get a used lower mile motor with a bad coil pack?

Chris.

about a year since I did a complete tune up. I used very good wires. Not sure the brand, but if I remember their Blue Wires at NAPA. Their the ones that people say they smell nice. You can not judge the quality of spark plug wires by the "smell"!

I did read over the years on this forum about using AC Delco Plugs. I wanted to use them but the mechanic I use, has done thousands of cars and in racing, done lots of tests. He recommended a different kind. Can't remember what he put in (I could guess and say NGK, but this is a guess). We have a massive snow storm right now, we're getting dumped on with snowball sized heavy snow. Will wait until morning to check what plugs for sure.When I use NGK ( V-Power TR-6) I have to change them every year, otherwise I will begin to get "Fishbite" @ low rpm in OD.

Another person I know in the automotive business, did tests on a whole bunch of different plugs. His finding where that there was no difference in performance. One difference was his test was done on very high performance engines.Were these test conducted using the DIS ignition system?

As I'm writing this, I remember it did this on my last motor. This newer motor I put in has different coil packs. Wonder what would be the chance my old motor has a bad coil, and I get a used lower mile motor with a bad coil pack?Chris.50/50 chance. I recently installed three NEW coils on a customers car and one or two, out of the three were bad. You need to invest in a spark tester! Less than10-bucks!!!

http://www.toolfetch.com/media/45264.jpg

I can just about guarantee that the NGK, (No Good Kind) spark plugs are causing the problem. Don't misunderstand, NGK are decent plugs, but not in a GM. Try a set of AC Delco 41-101 with a gap of .060 and they will perform and last better than any other plug in your engine.

I can just about guarantee that the NGK, (No Good Kind) spark plugs are causing the problem. Don't misunderstand, NGK are decent plugs, but not in a GM. Try a set of AC Delco 41-101 with a gap of .060 and they will perform and last better than any other plug in your engine.
Seconded or the equivelant Denso!!

Seconded or the equivelant Denso!!

Especially since many "AC/Delco" plugs are manufactured by Nippon-Denso.

I can just about guarantee that the NGK, (No Good Kind) spark plugs are causing the problem. Don't misunderstand, NGK are decent plugs, but not in a GM. Try a set of AC Delco 41-101 with a gap of .060 and they will perform and last better than any other plug in your engine.

I just have to ask... why is NGK a problem in a GM DIS system? I have run them for years with 0 issues... NGK TR55 # 3951, one range colder than stock...

On my Modded 95 Trans Sport I will be changing the plugs, but will only be doing so as the Factory wires are taking a dump( they were the wires that came on the 06 L26 I bought...lol ) and I never replace wires without plugs..

The only time I have ever had an issue with an NGK is when I broke the insulator...

Bosch Plats do not work with GM DIS systems and will cause issues in short order..


I have used AC Delco 41-606, 14, Autolite 606 and 605, NGK TR55 and TR55 Plats..


Chris, I agree with what has been stated about your ignition system, possible to have a bad plug, bad wire or coil... Its also possible that you may have a pissy injector...

Reach, heat range and taper seat, those are the three most important things. All 3 must be correct, AC Delco plugs are designed for your engine, and all three are correct. You can see the differences if you hold an AC Delco and another brand side by side and look closely. The configuration of the center electrode insulator determines heat range. Longer insulators will run hotter, shorter ones will run colder. You can "read" the plug after it has a few miles on it. If the heat range is too cold, it won't ignite the mixture fast enough, the engine will run rich, the plug will have a black sooty deposit on the center insulator, will be prone to premature fouling, and will cause excess carbon build up in the combustion chamber. The fuel mixture will not be fully ignited when the piston reaches TDC causing a lack of power and a waste of fuel. If it's too hot, the mixture is ignited too quickly, the engine will run lean, and the center insulator will have a white color to it and can also burn the ground electrode too quickly. The fuel mixture will be completely burned before the piston reaches TDC causing a lack of power and spark knock, (detonation) and can burn a hole in the piston. On a side note: Engines with knock sensors will compensate for spark knock which decreases the possibility of burning a piston, but it also decreases fuel mileage. Either way, the longevity of the plug is shortened. The reach determines where the spark is initiated in relation to the air fuel mixture in the combustion chamber. If the reach is too long, it can disrupt the mixture flow in the combustion chamber, and the piston could contact the plug. If reach is too short, it will delay the ignition of the fuel mixture. The taper seat must exactly match the taper in the cylinder head to assure a good seal. I'm not an engineer and I don't design engines, I leave that to them and use what they say is best. They're usually right ;)

OK, to answer each thing, without having to go to each message;

"You can not judge the quality of spark plug wires by the "smell"!" Of course not. When the mechanic told me to get the NAPA Blue wires, he added that they even smell nice. When I posted here on the forums, the people who replied also mentioned the NAPA Blue Wires smelled nice. Since that was one of the things people where familiar with, and I Did not know what exact model they where, I used the smell nice as a way to describe them, since the forums are familiar with that.

50/50 chance. I recently installed three NEW coils on a customers car and one or two, out of the three were bad. You need to invest in a spark tester! Less than10-bucks!!!
Will the spark tester test the spark under load? I was told a coil test doesn't test them under load, so it won't show up as a problem. Will it be the same as that, or will a spark tester test under load?

I just have to ask... why is NGK a problem in a GM DIS system? Same reason why two different shaving creams, with the exact same contents, but a different color on the label, a person thinks one works better.

I have run them for years with 0 issues... So have most others who use them.

I checked into the AC Delco 41-101's. The $50 is to much right now (not working). If I did use the 41-101's and it ran the same, would that mean there's no different then whats in now?

I could always try the ACDelcos when I got the money, just to see what would happen.

Maybe I should replace just the one, #5 cylinder with an AC Delco? :) :0

Thanks for the replies,
Chris.

The shaving cream analogy doesn't cut it when it comes to AC Delco and NGK plugs: Two different manufacturers, two different parts. The problem is not the DIS system, it's a matter of heat range, reach, and the angle of the seat. NGK works better than AC Delco in a Toyota, it's a matter of using what was designed for the engine. You're asking us for professional advice, and we're trying to help you.

Stick a 41-101 in #5 hole and see what happens. If that fixes it, you only need 5 more. If not, you're that much closer to having the correct plugs in there anyway ;)

Chris if price is an issue, use the Ac Delco 41-606, this is the copper plug meant for use in the 3800 Series II L36... Should run $1.50-1.90 each... You can also use the Autolite 606 plug if you wish...

Napa Wires are good, and if you got the lifetime warranty and have issues with the wires they can be returned for a new set...

NGK is not a problem with the GM DIS system, Bosch Platinum however is...

There is one side of me that thinks it wouldn't matter a lot, but I can understand what your saying.
Then again, some say that in the last couple years, NGK makes plugs for AC Delco.
Here is a photo of both side by side.

http://i995.photobucket.com/albums/af78/happydog500/ACDelcoNGK.jpg

Would it cause a problem if I replaced just one? Why the iridium? What about AC Delco regular?

Chris.

You don't have to use iridium, it is a good plug with a long service life..

The 41-606 should give you roughly 30,000 miles and are way cheaper..

You can replace the one plug to see if the plug is the issue, if that corrects the problem then go ahead and replace the rest of the plugs... Once you do that Erase the P0305 code and then take it for a spin and see if you have the same issue...

My experience has mostly been plug life with non AC plugs at 30k pr less the center electrode shows way more erosion with other than AC plugs.

I am going to say this again....

AC Delco 41-606

No reason for the guy to spend 50+ on plugs when he is hurting for $$$... all 6 of the 41-606's would run near $11

OK, Thank you guys very much for the help. I took the #5 plug out, can see it was cracked in two places. http://i995.photobucket.com/albums/af78/happydog500/CrackedSparkPlug.jpg
I changed it (glad it was one in front, not between the firewall). The fish bite went away.

Want to explain why I went a year with a problem. I misunderstood the problem. I read where these transmissions have the common, "valve body problem", where it feels like a misfire, but it's really in the transmission. I misunderstood that this doesn't apply to my transmission (T60), but the T65.

I was under the impression it was not a misfire, but transmission problem.

Here is another problem (maybe?).

The plugs that are in my car is the, NGK TR55GP. I looked up the cross reference to the AC Plugs in my manual (41-921).

When I cross reference the AC "41-921" to NGK, I get NGK "PTR 4B-15".

How far off is PTR 4B-15 from TR55GP?

This ended up being an easy fix, thanks to you guys here at the forums. Thank you very much for the help.

The guy at O'Reilly's Auto said the plugs "sure wore out quick, look at how little the point is."
This sent my friend in a manic state. "this is why I hate coming here" he repeated.

Sad I went a year with a drastic fish bite, but glad I got it fixed now.

Thank you,
Chris.

This is the problem with using anything other than AC Delco plugs, they don't cross because they're not the same. You can look at cross reference books all day long and not get the same number. Anyway, glad you got her fixed. Thanks for posting back.

This problem was not the plug type, heat range, or the brand; but damage when installed!

http://i995.photobucket.com/albums/af78/happydog500/CrackedSparkPlug.jpg

I agree 100% HotZ28......

I have done exactly this to a couple of NGK TR55 plugs... Causes a heck of a miss... Lets also keep in mind its a waste spark system, and if you have one bad plug it will affect the function of the opposing cylinder, this will cause nasty misfires...

Chris I am glad that you got this fixed... The find to your problem was long overdue..

Who put the Plugs in? Was this done by your friend?

The plugs that are in my car is the, NGK TR55GP. I looked up the cross reference to the AC Plugs in my manual (41-921).

When I cross reference the AC "41-921" to NGK, I get NGK "PTR 4B-15".



The NGK PTR 4B-15 was the other OE spark plug GM installed but mainly in the L67 SC versions of the Series II 3800 engine. Double platinum. The Delco 41-921 double platinum was the other prevelant plug from the factory. Good for up to 100K miles. No longer being manufactured. The current AC Delco recommended replacement plug is the Delco 41-101 which is an Iridium. This plug is made by NGK for GM. Also, NGK TR55IX (Iridium) plugs work like a champ in this engine as long as installed properly.

Yes, it was "my friend." He has been a very good mechanic, and person, but a couple years a go he started to hang around with people that I wouldn't. He changed, got kind of a jerk. At that same time, he had these people I did not like work for him.

I would like to go with the recommended plugs next time. I hate iridium plugs tho. They're supposed to work good, but I see a pocket of people who have problems with them. My friend (not the same one) put them in his car and they got "all corroded" very quick. I read in several different places where he is not the only one that happened to.

Reminded me of the "new" anti freeze they used years a go. It was supposed to work better, last longer, but lots of people (not all) reported problems.

Man this car runs good now. I had fish bite for some years before I ran this motor for the last year. Sure feels nice. Nice to know my transmission is better then what I thought.

One bad thing is, now that my transmission is not the problem, makes it not as a priority to change it. The thing is, it has a little howl to it. This means theirs not as much of a problem I'll fix putting in a different transmission.

Instead of changing a trans to solve major problems, I'll do all the work just because of a Bering.

Chris.

Good to hear Chris...

I just took the NGK TR55's out of my 3800 L26 in my van... Been in there from day one with the engine install, included the plug wires from the L26... Pulled them yesterday to find that the plugs were in good shape for 20k miles, Being run to 6200 Rpms, changing the PCM tune trying to get it close over and over again.... Having a coupld of plug wires show up with issues... It was the reason the lugs were changed in the first place and the wires are new AC Delco wires... Nothing wrong with an NGK in a 3800...


The howling you hear, does this happen with speed? Or does this howling change with gears?

If I'm driving around town, the noise changes if I slightly let off the gas. I think it's pretty much the same as I drive. Cant hear it when I'm going faster, road noise blocks it out. If I'm just driving down the road at 30 you can hear it (not just at 30).

I'll go out and do some tests and describe when it does it.

With my plug fix, I either have a gas gauge stuck/broken or I'm getting a lot better millage!

Chris.

You should be getting better mileage...

You have a bad wheel hub assembly...

Does the hum change on left or right turns?

No, did that test already. Doesn't change when I swerve all over the road. I'm sure it's a inside barring. Probable the one that is known to go out in these Transmissions.

Chris.

No, did that test already. Doesn't change when I swerve all over the road. I'm sure it's a inside barring. Probable the one that is known to go out in these Transmissions.

Chris.

Thrust washer maybe,.... what bearing is said to fail?

I have seen the pump shaft roller bearings fail, but its takes a lot to get there..

.... what bearing is said to fail?
I saw a web site devoted to the 4T60 Transmission. It listed the usually "known" problems with them. One that was listed was a bearing of some kind. If I remember right, it mentioned a noise as you drive down the road.
I remember something about 4th, but maybe it was separate from the bearing part.

I'll try and find the web site.

Chris.