My 98 has a problem when accelerating slowly at about 45MPH to about 55 MPH. If I stomp on it it moves out w/o the hessitation/miss. I am not getting any DIC codes related to any engine sensor. I am at a loss to what's up with this. I have about 50K miles on the car and until the past three months I never had any problems with the motor/electrical/sensor systems. It is an auto tranny model convertible.

Any chance that it could be an O2 sensor or a MAF problem? I was hoping to find a code that would point me in the right direction but there's no current codes at all and the only codes showing are HVAC issues, power seat sensor position , and a few communications codes. All are history codes.

Any help will be apreciated.

Roy in Phoenix

 

Check - ohmm your plug wires

Check - plugs, it is very possible (even if new) that one is cracked

This has happened in the past to some of us, for me it was a wire others it was a cracked plug!

Thanks,Matt

 

TY, I'll keep that in mind. With yours, did you have a slight miss in the 45 to 55 MPH range or was there a constant miss?

Again TY for the reply

 

It was at speeds and fine at idle and low RPM - when it was gotten on or around higher MPH it started to miss - turned out to be the #7 wire

Thanks,Matt

 

If I can not find another reason for the missing, I'll replace all wires and the plugs. They are the orginals and have about 50K miles on them.


TY for the quick response.

Roy in Phoenix

 

Roy,
No need to just go out and replace them!

Take an Ohm meter and check each plug wire to see if they all ohm the same!

Pull the plugs and visually inspect them - you can also test them if you would like - if you change plugs go with NGK TR-55's gapped at 55

Thanks,Matt 661-406-7516

 

Here is how to test the Spark Plugs:


An Ohm meter, which is part of a multimeter, can only check a spark plug for a short circuit or a breakdown of insulation resistance. A good spark plug should show an open circuit between the center electrode and the tip. Any resistance at all would mean the plug is bad. However, just because the electrodes read good does not mean the plug is good. It could have the tip missing or any of several other problems. So the Ohm meter test can show if the plug has a short or resistance, but it can't prove that the plug is good in all respects.


Instructions.Test for a Bad Spark Plug
1
Connect test leads to the multimeter by plugging them into the jacks.

2
Set your multimeter to the "Ohms" position.

3
Touch the test leads together. The meter should read zero Ohms.

4
Move the test leads apart. The meter should read infinite. Note the reading.

5
Remove the ignition wire from the spark plug.

6
Touch one meter lead to the terminal of the spark plug and the other lead to engine ground. Press the points of the meter leads firmly to the metal to ensure a good connection.

7
If the meter reading is anything other than what you saw in Step 4, the plug is bad.
.

Thanks,Matt

 

Matt,

TY for the tip. Excuse me if this seems like a dumb question but are you suggesting that I leave the plugs installed into the block and remove the plug wires using the end of the plug as one end of the testror's probe and the engine block for the other meter prob? Also can I check the plug wires as well, I suspect them before I would a plug.

From what I have read the NGK TR-55's are the best plugs to go with if I do replace them.

Do you have any suggestions for a set of spark plug wires also. Several have recomended Magnecore 8.5mm or GMPP red wires.

TY for the advice.

Roy in Phoenix

 

Roy,
You can pull each wire and check them individually! put the test meter lead on one end of the plug wire and the other on the oposite end and see what the OHM's are!

They should all be right around the same - they are short so the OHM's or resitance should be really low.

MAGNACORE wires are pricey (if I remember right) GM RED wires are good and a lot of guys run them and they are not too expensive, I have run MSD RED wires for a long time and you can get a good new set off AMAZON quite cheap. So all these wires are good

As far as the test for the Plugs, to visually inspect them you would need to pull each one -

To use the testor you will leave it in and one end will go to the Frame (Or a good ground) and the other to the end of the exposed plug (still in the block) this can be a bit tricky with a cracked plug - that's why it's also good to check them visually so you can also see the elctrode -

It is also possible that one of the arms of the electrode or the center could be bent or missing (let's hope it's not missing ) this too can cause the higher RPM and MPH chug you're getting!

Let me know if you need a little direction on removing the plugs - I have the easiest way of doing it - and it saves time and frustration!!!!

Thanks,Matt

 

Excellent price from our Forum Vendor

http://www.mcssl.com/store/cc-perfor...81a6a08596362b

http://forums.corvetteforum.com/c5-t...-anywhere.html

Thanks,Matt

 

Matt,

Thanks again for the advice. I sure could use so heads up on changing the plugs and wires. I have read that most plugs are pretty easy to get to but there is one that can be a real problem. I have also read that pulling off the orginal GM wires can often damage the plug terminal ends (especially if you have 50K mile or more) so I just figured that if I'm going to dig into this,I might as well go ahead and replace all of the plugs and wires.

BTW I have been having a hard time finding the NGK TR-55's at any of the parts houses in Phoenix (Checker, Autozone, etc.) Also no one here seems to have the GMPP wires in stock or even has a way to get them so I was looking at MSD wires as an alternative and NGK TR5 plugs as an alternative. Their book says that NGK TR-55 is replaced by NGK TR5 or NGK TR5GP. Not sure if these are any different or not. I can get both the GMPP wireset and the TR 55 plugs from an oline sorce, but I always like just getting the parts I need locally if possible.

Send your advice in plug replacement, I can use any help that I can get.

TY<

Roy in Phoenix

 

I had a miss and found a burnt plug wire. If you start the car in the dark you will see any arcing around the wire very easy.

 

TY, I'll give that a try.

Roy in Phoenix

 

Matt,

TY for the links to the forum vendor for MSD wires and NGK plugs. I'll order both from them, they have a great price and the NGK TR-55's.

Can you send me the your tips for changing plugs and wires? I could sure use any help that I can get.

TY,

Roy in Phoenix

 

Hey Roy,
It's actually quite simple:

(1) Remove the plastic coil covers on both sides

(2) Unplug the WHITE clip in the "CENTER" of the Coils

(3) Pull all the Plug Wires

(4) Take a deep 10 mm socket and ratchet and remove the coil Packs/Brackets from the Valve cover - yes they will come off in one piece. You can see where they attatch to the valve cover because there is a hump where they thread into. You see what I mean when you pull them off.

This helps you get your arm down there, and on the drivers side you do "NOT" have to remove the fuel line (unless you know how to and have the proper removal tool)

(5) Now get a 3/8 ratchet and a 5/8 spark plug socket (the one that has the rubber in it to hold the plug stable and in the socket-this really helps when it comes to "NOT" cracking a plug, it's worth the extra $3-$5 for one )
No extension is really neede or at least I don't need one - if you do use anythng use a 3/8 swival instead

(6) Remove 1 Plug at a time - get a Sharpie and mark each plug with the number cylinder it came out of. (This will allow you later to check the gap, tip, color, etc to see what was going on in each cylinder)

(7) Install each plug one at a time - make sure you gap the NGK TR-55's @ 55 before you install them. (I usually start from the front to back )

If you get frustrated walk away and get some water or something (drink beer later )

Do the same for each side and then when all the plugs are in!

(8) Re-Install the coil Brackets/Packs and plug in the "WHITE" Plug for the coils

(9) Install all the wires and make sure you feel the snap/pop when you install them (sometimes it takes the use of both my hands fingers to do the furthest back wires that attatch to the coils and somethimes the plugs too)

(10) Makes sure everything you removed (wire wise and clip wise is on and re-plugged in)

(11) Now fire up the motor - YES! - before you put the coil covers on

(12) If everything is all good then install the coil/engine covers and you are ready for the test drive

Then the most important is to let me know and the rest of us how it goes

If you run into any trouble you can give me a call too: 661-406-7516

Thanks,Matt

 

As a wild guess, have you checked your grounds on the car?
I have found that some crazy things happen when the ground gets a little corrosion on it.

 

I would clean out the MAF next if the spark plugs/wires were found not to be the cause. You can get a CRC MAF cleaner at any autoparts store. its a good time to inspect the air filter and replace if needed.

 

You're welcome Roy!

Again give me a call on anything - especially since we have the same year - I have a wealth/plethera of info to share with you for any related problem or part.

And what ever performance stuff you want to do I can give/share all my info and knowledge as well as experience!

Thanks,Matt

 

Roy this is an excellent suggestion to do as suggested.

You might just go ahead and do it either way, AFTER you get the other stuff straightened out first.

Man I can't wait for you to get your parts!

Thanks,Matt

 

Matt,

Thanks again for the offer, I'll probably taclkle the wires and plugs next week, going to order the new stuff from CC automotive today.

I'll let you know how things go.I just hope that the wires and or plugs are the cause for the miss I have.

Roy in Phoenix