Not really sure if I would call my a misfire, but a coil is getting replaced today. I was sluggish at times on the highway. The stealership said it threw a code and was the coil. He said something about each plug has a coil!?!?!

 

Yea, We have a Coil on Plug setup. The Coil actually seals off the sparkplug area. No sparkplug wires either really. All you have is a 3 inch stem that comes out of the coil that the plug fits into..

 

It could either be bad plugs or the dreaded exhaust valves going bad...did you ever see that TSB? I don't have the number, but there was a TSB for the exhaust valves and misfiring was a symptom...

 

Yea, I saw it. I don't think thats my problem...


Engine - Misfire/DTC P0300 Set

Bulletin No.: 04-06-04-081A

Date: November 12, 2004

TECHNICAL

Subject:
Engine Misfire, P0300 (Replace Exhaust Valve Springs and Seals)

Models:
2004-2005 Chevrolet Colorado
2004-2005 GMC Canyon

with 3.5L Inline 5 Cylinder Engine (VIN 6 - RPO L52)

Supercede:

This bulletin is being revised to correct the part quantities and a part number. Please discard Corporate Bulletin Number 04-06-04-081 (Section 06 - Engine).

Condition

Some customers may comment on the Check Engine Light flashing. Additionally, some customers may comment on a light engine knocking or mis-fire noise during warm up or on a decel after the engine is fully warmed. Upon investigation, the technician will find a misfire code P0300 through P0305.

Correction

Perform the diagnosis for the P0300 code as found in the appropriate section of Service Information. If no concern is isolated through the diagnosis, then replace all of the exhaust valve springs and seals. Refer to the Valve Stem Oil Seal and Valve Spring Replacement section of the Service Information for the proper procedure

 

Would the misfire be heard as a metal pop or ping noise threw the exhaust. I get this pop, sometimes loud fart noise when I start it up and now often on decel. Dealership found another 5cyl 5spd doing the same thing and said its normal, believed to be a design issue with the exhaust causing backpressure. not described by them as a "misfire"

I'm worried it's the start of the bad spring problem, no check engine light yet.
Sound accurate? is this the noise your hearing?

 

No, I hear nothing. Absolutly nothing. But I do Agree with you. After reading the tsb on the misfire with springs, It does sound like you have the beginning of that. At this point, I'm at a loss. The Stock plugs looked great. But they got changed anyway. So at this point I'm looking at a bad injector and or a coil. I re-ordered the coils, So if the misfire follows, We'll say coil.........

I'm going to start a new thread on this, But since I found it while working on this topic, I stick it here too. ON the I5 engine, If you look beteen the intake manifold and the firewall there is a black line running into the valve cover just under the edge of the intake resonator. This black hose prolly has a piece of black foam over it. With the engine running, Does it sound like its leaking? We looked for a good hour last night and couldn't find anything. So at this point we're wondering if there isn't jsut that much flow through the hose and they keep the foam on it to dampen the noise?? Anyone else hear this sound?? The sound SHOULD change pitch when you play with the foam..........

 

How do I know if TSB# 04-06-04-081A, the one mentioned above applies to my truck? I'm not sure what the VIN number noted represents. My truck starts up kinda rough, to my definition, but has never backfired or knocked, it is a 2005

 

vin 6 would be the 8th digit in the vin. the 8th digit represents engine.

6 = i5
8 = i4

the tsb applies to all 04

and some 05's, it is vin specific in 05

 

Okay, so how do I know if my 2005 I-5 falls under the effect of this TSB?

 

Okay, so how do I know if my 2005 I-5 falls under the effect of this TSB?

i will find out what the vin cut off is on monday.

 

I have about 19,000 on her now, warranty is going to last me less than another year. Just wanna fix anything that's not right. Thanks for helping out.

 

Quick question fellas, can the scanner still read the code even if the check engine light is not on? This engine misfire thing is worrying me, my engine light comes on quite a few times. But its never stays on long enough to take it to dealer. My truck seems to run fine and ive been to the dealer once and didnt find anything. It really bugs the hell outa me.

 

Quick question fellas, can the scanner still read the code even if the check engine light is not on? This engine misfire thing is worrying me, my engine light comes on quite a few times. But its never stays on long enough to take it to dealer. My truck seems to run fine and ive been to the dealer once and didnt find anything. It really bugs the hell outa me.

yes.

it takes 3 consecutive passing drive cycles to turn off the light.

and 40 consecutive passing cycles to delete the code from the PCM.

 

That brings up a good point too, the check engine light. Like I said before I don't think my truck is misfiring, but it does start up rough that's why I'm concerned. The check engine light has never come on, not even once. So if therre is something wrong I don't know about it!

 

Okay, so how do I know if my 2005 I-5 falls under the effect of this TSB?

i will find out what the vin cut off is on monday.

VIN Breakpoint 58261313 and Build Date 04/13/2005

 

On rare occasions, a P0300 DTC may set on low mileage vehicles due to random misfires that are not felt by the driver but count on the Tech 2. This may be the result of an air conditioning, power steering pump, or water pump pulley that is out of round. Although this could occur on any of the engines listed above, it is most likely to occur on the 3.5L Engine (VIN 6 - RPO L52) due to it having an odd number of cylinders.

could also be related.

 

My comment is neither scientific or particularily objective, just an observation only. In reading all the posts regarding driveibility, misfires, rough idle etc. the only commonality that I seem to see is related to the PCM. My truck has an I-5 so I guess I focus on posts that relate to that engine. There are reported to be a number of programming changes and/or software updates for the PCM that dealers have applied to members trucks. Spoolin ex found some GM information suggesting that bent pulleys etc. MAY cause a code to register. What I was taken with was the GM comment; " although this could occur on any of the engines listed above, it is most likely to occur on the 3.5L Engine (VIN 6 - RPO L52) due to it having an odd number of cylinders".

We know the I-6, I-5, and I-4 are alike in that they share many parts. Just wondering out loud if the PCM is as well shared, and if by design it is unique to even cylinder engines and is adapted to our odd cylinder I-5. I don't know if this even plausible and how it might be validated. Just a thought.

 

YOu would still have diffrent air/fuel ratios for each of the engines, it could be they have all the same formats but that is all.

The type of gas may give you a misfire, it may be too lean, if i recall V-power fuel is high octane. You shoud not run high octane gas in the winter. Its a heavier fuel and could foul your plugs. I would stick in mid-grade gas and see what happens.

As for the Iridium plugs, i installed my plugs like 15,000 miles ago. I was the first on this site to install those plugs.
I love them, they are very responsive plugs. that was my first up grade on the I-5. They do make a diffrence.

 

My truck had to have the cam shaft actuator replaced in it. What happend was i was at a light at idle and it strted miss firing bad then died. when i started it back up the sel light came on and had a message stating reduced power. the dealer ened up replacing the cam shaft actuatur and i havent had a problem sence.

 

thanks for the info spoolin ex. Unfortunately my truck falls within that vin cutoff. I'm going to talk to someone at the dealership, thanks again.

 

Great. My vin is 58163777! Hmmm, wonder if this explains my rough idle and ticking noise. Yet another thing to add to the list to see the dealer about!

 

My VIN is also below the cutoff....I hope if something does start acting up that it does before 36k!

 

Well, I took the truck to the dealer yesterday. My complaint was rough first start of the day. No check engine light, no knocks. I took it in after reading the posts on the site. They said no codes showed up in the computer. Half of me hopes that nothing is wrong and nothing will change. One quater of me wishes I didn't bring the truck in, and the other quarter is that I wish I bought a truck that wouldn't need to have part of the enginge dissasselmbled after one year and 20,000 miles. They are replacing the springs. So what's the word on this valve spring thing causing problems later on?

 

And now...my truck too...threw the p03005 code or whatever...took it into the dealer and now waiting for a new cylinder head to be shipped in...what is up with that!!!

 

I made a new thread, I think it possibley relates to this problem, "Metal in oil filter". I have noticed some people are having to replace pistons, I'm finding aluminum in my oil filter. I think this 3.5 liter is chewing up pistons due to a misfire, and the porblem is not the valve springs, or at least that's not the solution to the problem by itself. I was talking with the guy I usually takes care of my cars, he thinks it is the cellunoid that controls the cam that is screwing up the timing. The valve spring thing is bull, the valve springs are going to keep the vavles closed at high RPM, not low. I'm going to another dealership tommorrow, other than the one I have been using. If your having this so called "valve spring issue", tell the dealer to think about replacing the cellunoid that controls the exhaust valve cam. I'll give an update when I know more.