Cap and Rotor

Hi guys I have a question. I did a tune up on my 97 Bravada last fall. At the time it had 68K miles on it. I replaced the plugs, fuel line filter, PCV, and put in a K&N air filter and cleaned the MAF sensor.

My truck now has 75K and as of late I noticed it seems a little sluggish, not too bad but a little hesitant when accelerating. I am wondering if I should replace the cap and rotor? I did not replace that during the tune up.

Is there something else that could be causing the sluggish response? I am currently getting about 19-20mpg on the highway and 15.5mpg in town.

Thanks for any help as it is greatly appreciated.

i would replace the cap, rotor, and plug wires. there are alot of things that could cause this. but this would be the most obvious of all. also check fuel pressure and check vaccum lines for leaks.
i dont know much about k&n filters but how often do they need cleaning?

They need to be cleaned about 50k miles

Air Cleaners vary on how dusty is is where you drive, and a few other factors can be worked in as well.

I would start with the cap and router, plus pull and check your plugs. Most people on this board say that origional plugs are the only ones that'll work right.

Thanks for the info guys. I appreciate it. I will be changing the cap and rotor very soon.

When I did my tune up I used Autolite platinun plugs from Autozone. They seem to be working fine so far. Are these a bad choice?

Yes, indeed it was a bad choice. Take them back and ask for AC Delco Plats. The Autolites don't have the heat range our trucks need in a plug

Yes, indeed it was a bad choice. Take them back and ask for AC Delco Plats. The Autolites don't have the heat range our trucks need in a plug
What about Bosch Platinum 2's? are they alright?

No, our trucks do not respond well the Bosch plugs. They do not have the same heat range of the Delco's. We need plugs within a very high heat range, and Delco has been the best to provide that range.

ac is the best plug for the money. bosch and champion dont do well even if platinum or gold. dont forget to change your plug wires as well.

Thanks for the info guys. I appreciate it. I will be changing the cap and rotor very soon.

When I did my tune up I used Autolite platinun plugs from Autozone. They seem to be working fine so far. Are these a bad choice?

I think you answered your own question. They aren't doing ok for you since you're complaining about your trucks performance. Stick with AC Delco's it's worth it in the long run.

What are you referring to when you mean "heat range" ?

Spark plugs have a specific heat range that they are specifically built to operate in. The other plugs do not stand up to this specification in our vehicles.

ac delco plats are gm replacement parts and are the best for our engines. yea they are a bit pricey but are worth it if u want long term realiability.

Hate to break it to you, but Autolite, 50% of AC Delco, and SplitFire are all made at the Honeywell plant in Fostoria, Ohio.

Not a lot of difference other than the brand and the number of 'ribs' on the ceramic insulator.

ac delco.! lets take what booch said here in post number 14 for a second, yes they are made at the same plant, but, my buddie makes cheese, and at this same plant they make pepper jack, american, swiss and about a dozen other types, no 2 cheeses taste the same, no two plugs are created equil, you do what you want with your vehicals, but our blazers call for, work best, and last longest on ac delco platnum plugs, bottum line, every thing else is pure shit, including bosh 4, champion, autolite (ford plug) and any other redaly available plug... tommy boy says it best 'you can get a good look at a T bone by sticking your head up the bulls ass, but wouldnt you rather take the butchers word on it?'

As far as I know, the brand has nothing to do with the temperature range of the plug, it all depends on the part number ordered.

That is incorrect. No other plug has the heat range of the Delco ones.

delco plats are one of if not the hottest burning plugs made

I am just wondering what do you mean by heat range and hottest burning plugs? I thought that plugs were rated by the length of their tips and how far that they extended into the combustion chamber. The more a plug extends into the chamber the more heat is transfered to it and to the insulator(hot). The less the plug extends into the chamber the less heat is transfered to the insulator (cold). It is bad for a plug to hold too much heat it will act just like a glow plug and detonate the incoming mixture before the piston chamber fills (knock & Ping) eventually destroying your engine.

Can anyone provide some internet links for the comparison of the "heat range"? I would but I am not sure what I am looking for. This would provide an end to the war here...

Here is one explanation:
http://www.carcraft.com/techarticles/64378/

there is no war, by hot i mean hot, temperature, a wood fire is hot, but an oxy accedelien torch is hotter, they are both flames but the tempertaure of opperation is much 'hotter' on the second one, gm requires .060 gap and a strong hot spark in that gap, gm's theory of opperation is the bigger the gap the more molicules of air and atomized gas that can fit into that space, and they need a hot (blue not ornge) spark to proporly ignite and burn all the fuel in the cylender, a cool plug will let some raw gas by because it will be unburned, eventually this can burn the vehical down in worst case or junk the cat which is needed on all vehicals 96 and newer due to a post catalitic converter oxyegen sencer...

there is no war, by hot i mean hot, temperature, a wood fire is hot, but an oxy accedelien torch is hotter, they are both flames but the tempertaure of opperation is much 'hotter' on the second one, gm requires .060 gap and a strong hot spark in that gap, gm's theory of opperation is the bigger the gap the more molicules of air and atomized gas that can fit into that space, and they need a hot (blue not ornge) spark to proporly ignite and burn all the fuel in the cylender, a cool plug will let some raw gas by because it will be unburned, eventually this can burn the vehical down in worst case or junk the cat which is needed on all vehicals 96 and newer due to a post catalitic converter oxyegen sencer...

Very well put. Now that you know what it means, AC Delco Platinum plugs are the only plugs the provide our vehicle with the proper "heat range" for optimal combustion.

Very well put. Now that you know what it means, AC Delco Platinum plugs are the only plugs the provide our vehicle with the proper "heat range" for optimal combustion.
now that this is established, i've woundered something else; whats the difference between delco plats and delco rapid fires?

Plats are platinum, rapid fire are copper. If your vehicle is 1996+, you need plats

back to the "title" of the thread...if you have crank and air/fuel and at least some spark, but it still won't start, it's likely the cap/rotor. i realize this isn't in response to the op's question, but is just an FYI that is related to the title (i replaced mine 2 weeks ago and it fixed my "mystery" problem.)

I usually have no issue buying Aftermarket parts and Bosch parts are typically pretty good....however I will testify that only Delco plugs work properly in a Vortec V6. I ran Bosch for a week and had misfires on all cylinders.

i use some aftermarket parts at work, not all are bad, but some systems on the newer vehicals are just pickie as to what they get tossed at them

My 99' 4x4 is doing good with my Autolite's that I installed in it. But I have only put on about 11k miles on the plugs.

autolite is a ford plug

ac delco.! lets take what booch said here in post number 14 for a second, yes they are made at the same plant, but, my buddie makes cheese, and at this same plant they make pepper jack, american, swiss and about a dozen other types, no 2 cheeses taste the same, no two plugs are created equal, you do what you want with your vehicals, but our blazers call for, work best, and last longest on ac delco platnum plugs, bottum line, every thing else is pure shit, including bosh 4, champion, autolite (ford plug) and any other redaly available plug... tommy boy says it best 'you can get a good look at a T bone by sticking your head up the bulls ass, but wouldnt you rather take the butchers word on it?'

Wow; is spelling really that tough?

At the time I left Honeywell (about 2 years ago), they were making about 40% of the AC-Delco / GM plugs, and this percent was growing. Honeywell also made the Ford plug, called MOTORCRAFT (not Autolite). They even make the 'platnum' versions as well, which are 'redaly' available. 'Bottum' line; plugs manufactured by Honeywell are of a very similar design, to allow flexibility in production.

I absolutely agree that all plugs are not the same; however, the Motorcraft, Autolite, and AC plugs that are made at Honeywell's Fostoria, Ohio plant are pretty much interchangable for a given application.

dmbrisket, you made some comments earlier that only AC Delco has the heat range needed by a Blazer; this is utterly ridiculous. Heat range is defined by the temperature of the spark plug electrode, sidewire, and insulator assembly in the combustion chamber during normal operating conditions. This temperature can be controlled during the plug's design stage by adjusting how much of the ceramic insulator assembly is touching the inside of the steel shell; the more contact, the faster heat will dissipate from the electrode and sidewire, through the insulator and shell, and ultimately into the engine head.

For a fairly simple explanation, check out these links;

http://www.autolite.com/pdf/HeatRangeFacts.pdf
http://www.autolite.com/pdf/UnderstandingHeatRange.pdf

And some decent pics are here;

http://www.autolite.com/pdf/PlugTips.pdf

By all means you should use the plug of your choice; just be sure to do some research and make an informed decision, rather than one based on opinions.

... tommy boy says it best 'you can get a good look at a T bone by sticking your head up the bulls ass, but wouldnt you rather take the butchers word on it?'
LOL!!

I love that movie.

But along the lines of what booch was talking about; I installed a line in a plant that makes air filters for several brand names. They are all identical. Its been a while so I dont remember which brands. Different companies do share parts and/or engineering to reduce costs.

I would be curious to know more about this.

Wow; is spelling really that tough?
accually yes it is, i have a low spelling and reading with comp problem... but ive had the last crack from you guys on that, and alwase with stupid shit, what does the guy with the licence on the wall know? nothing, sorry but i am out, you backyarders have fun figguring out what your doing wrong and when, hope that every one else can come up with answers, to the intellegent on the sight, most of you have my e mail already, feel free to keep in contact, as i will probibly do so

DM isn't the only one on this board that has a form of dyslexia. I do as well.

They're finding out that it's a very common problem these days.

We all try our best to make everything as ledgable as possible, but it can be impossible at times. What we see can often look right to us, and I even have the opposite problem as well, where I see a word that's spelled properly but doesn't look right.

I've only made 1 comment on AF about bad spelling, and that's because the person made about 10 spelling errors while calling another member stupid.
I was more pissed of at the way he was treating the other member than anything else.

So would everyone please refrain themselves from making negitave comments about bad spelling or grammer.
There might be a reason for it.

If you don't understand what they mean feel free to tell then and they will come up with another way to ask or answer the question

Agreed, that was way out of line. You clearly knew what he was trying to say because you were able to copy/paste some of the mistakes he made to ridicule him. Don't come on here and act like a pompous ass just because you worked for Honeywell, no one cares. People come here to get good advice, not to be criticized. Take a good look at Brisket's post count, he clearly has a little bit more invested in this forum than you do.

Wow; is spelling really that tough?

At the time I left Honeywell (about 2 years ago), they were making about 40% of the AC-Delco / GM plugs, and this percent was growing. Honeywell also made the Ford plug, called MOTORCRAFT (not Autolite). They even make the 'platnum' versions as well, which are 'redaly' available. 'Bottum' line; plugs manufactured by Honeywell are of a very similar design, to allow flexibility in production.

I absolutely agree that all plugs are not the same; however, the Motorcraft, Autolite, and AC plugs that are made at Honeywell's Fostoria, Ohio plant are pretty much interchangable for a given application.

dmbrisket, you made some comments earlier that only AC Delco has the heat range needed by a Blazer; this is utterly ridiculous. Heat range is defined by the temperature of the spark plug electrode, sidewire, and insulator assembly in the combustion chamber during normal operating conditions. This temperature can be controlled during the plug's design stage by adjusting how much of the ceramic insulator assembly is touching the inside of the steel shell; the more contact, the faster heat will dissipate from the electrode and sidewire, through the insulator and shell, and ultimately into the engine head.

For a fairly simple explanation, check out these links;

http://www.autolite.com/pdf/HeatRangeFacts.pdf
http://www.autolite.com/pdf/UnderstandingHeatRange.pdf

And some decent pics are here;

http://www.autolite.com/pdf/PlugTips.pdf

By all means you should use the plug of your choice; just be sure to do some research and make an informed decision, rather than one based on opinions.

Lay off of the spelling crap. You may know how to spell but you do not know squat about spark plugs. :grinyes: :lol:
Any Gm mechanic/tech knows to use AC-delco in a GM
And any ford tech/mechanic knows to use Motorcraft in a ford And
Any cry tech/mechanic knows to use champion/mopar in a cry/dodge.
Autolite and bosch and other aftermarket crap do not get the job done.
And do not believe a word of that www. autolite crap
MT

Lay off of the spelling crap. You may know how to spell but you do not know squat about spark plugs. :grinyes: :lol:
Any Gm mechanic/tech knows to use AC-delco in a GM
And any ford tech/mechanic knows to use Motorcraft in a ford And
Any cry tech/mechanic knows to use champion/mopar in a cry/dodge.
Autolite and bosch and other aftermarket crap do not get the job done.
And do not believe a word of that www. autolite crap
MT

:werd: :grinyes:

Please read this thread, and feel free to add any usefull comments that I missed
http://www.automotiveforums.com/vbulletin/showthread.php?p=3982370#post3982370

Hey DM,
Don't let STUPID CHILDISH COMMENT'S from a FOOL spoil it for the rest of us. That's not fair to all the good guy's and gal's on this board who look for your help and advice for our trucks, many of which i've taken...

Dino....

I've got 60,000 miles on my Autolite wires and Autolite platinum plugs, and my engine is still running great. I noticed a miss at idle when the plugs hit 50,000 miles, and assumed that the plugs were the problem. I bought a new set of AC Delco Plats, but after changing the air filter the engine started running fine again, so I left the Autolites in. As far as cap and rotor I would recommend only using AC Delco, I've heard of a lot of people having problems with some of the cheaper ones.


As for the negative turn this thread has taken.....

Booch is obviously a smartass, and if he keeps up the insults he will get a vacation.

The comments implying that proper grammar isn't that important are incorrect. There are rules in AF's guidelines discussing this issue. No one is expected to be perfect or even near perfect, but an attempt should be made to make every post as easy to read as possible. We all make mistakes. Hell, I make them all the time, I'm sure that this post will have mistakes that I missed, but for the most part it should be legible. I've seen people get warnings and bans for making a lot less mistakes than dmbrisket 51. I (and others that have been here awhile) know about his problem and let things slide, but I've seen him go months at a time making very clear and understandable posts, so I know he can do it, and would like to see him put a little more effort into making such posts again. My main problem is that what I want to say comes out faster than I can type so I end up leaving out several words. I normally spend several minutes checking a post before submitting it, hoping that I can fix most of the mistakes. Asking someone to make their posts a little clearer shouldn't be considered a bad thing, it isn't about being mean to that person, it's about making things easier for everyone else. Now, pointing out the mistakes in a childish way simply to make fun of the person, such as Booch did, will get you a temp ban, and if you can't learn from that, a permanent ban.

Blazee, I know that with myself I might see properly for months at a time, and then It's like someone threw a light switch making it really difficult for me to both read and write. And this condition might only last a few hours or several months at a time.

It might be the same for DM, I have no way of knowing.

I always try proof reading whatever I write, and if I can't manage it I'll sometimes just shut the computer down for a while, and hope that I'm better soon.

That's why I really don't want to see anyone badmouthing someone over something as pittifull as spelling. There might be a good reason for it

I've got 60,000 miles on my Autolite wires and Autolite platinum plugs, and my engine is still running great. I noticed a miss at idle when the plugs hit 50,000 miles, and assumed that the plugs were the problem. I bought a new set of AC Delco Plats, but after changing the air filter the engine started running fine again, so I left the Autolites in. As far as cap and rotor I would recommend only using AC Delco, I've heard of a lot of people having problems with some of the cheaper ones.


I am running Autolite Plats in my Blazer right now. They have maybe 15k on them and I am experience a slight miss at idle. It is very very minor but I can feel it. So I may have to put in some AC Delco's to see if that fixes the issue.

Plus I am due for a cap/rotor change. :(

Cloud Strife, I hope that you change the cap and rotor first, then give a report on your findings.

Cloud Strife, I hope that you change the cap and rotor first, then give a report on your findings.
:1:

I am running Autolite Plats in my Blazer right now. They have maybe 15k on them and I am experience a slight miss at idle. It is very very minor but I can feel it. So I may have to put in some AC Delco's to see if that fixes the issue.

Plus I am due for a cap/rotor change. :(

A bad plug usually will miss under a load.
If you have a idle miss or rough running. Check vacume lines and pcv valve and clean TBI butterfly and MAF sensor if you have one.
Also while checking cap and rotor check side play in dist shaft.
MT

cap/roter will also miss under a load if its crusty