My hesistation is now fixed, here all that I did:

Intake Manifold gasket
Cap/Rotor for Opti
Water Pump (It was weeping )

These three solved my high end miss, but I still had a miss a idle and a hesitation off idle. I fixed this by:
I found a plug that was arcing ( not "Coronal Discharge", but an actual arc, see my last post on this topic for Coronal Discharge)
The plug was #2, the porcelain was cracked and it was arcing to the head. It was causing a miss at idle, and a hesitation off idle.

Scott

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1997 Z28 MM6 Moroso CAI, Flomaster American Thunder, Taylor, Air Foil, SLP Headers, Crane Ignition, MAF, HPPIII, 4:10's, Summit Girdle, Drilled Rotors,
13.75@ 100.98 MPH
2.055 60'

No New Times With Gears....yet.

 

I've read a few pages of this and have one question. What plugs are most of ya'll with the problems running?
I owned a 95 3.4V6 Firebird at one point and replaced the plugs with Bosche Platinums. Even though this car was no LT1, it suffered the same hesitation problem. I was told that the Bosche plugs act all F'd up on late model GM and Ford cars by a mechanic. I avoid them like the plague now and so far have had no probs with my 97 Camaro (thankfully). I have an auto trans with 62K on the clock, and have replaced plugs, wires, fuel filter, PCV, etc. It's probably not the great "fix" to everyone's problem, but if you're running those Bosche platinums, it might be part of the problem. Anyhow, just my $0.02.

Schantin
1997 Camaro Z28

 

would a coolant temp sensor really do that ??

shantin, ive had the delco platinums in


pressures fine injectors fine timing ok
no vac leaks????

its at the dealer now iwas just there but the tech was out with it on a TD thats what sucks they have to run the **** out of it to get it to act up and they have had it a week..

and they still have nothing

 

a poor functioning coolant temp sensor will create drivability issues. I pasted these in to give you an idea. Temp vs. Advance

Load vs. Coolant Temp

This table contains values vs. Load and Coolant temp that will modify the values commanded in other tables. When a value is read in this table for a given condition, that spark modification will be applied to the total commanded value to increase or decrease it.
PE vs. Coolant Temp

This table contains the Power Enrichment (additional fuel) that will be added at WOT vs. the coolant temperature when in PE mode (WOT)

good luck...





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'97SS, More Performance 396, AS&M cold air, Grotyohann LT, SLP 2ODL muffler, Magnacor, PCMFORLESS PCM, LS1 twin piston calipers, KVR crossdrilled and coated rotors, SLP stage II w/ KYB AGX, 6M, Star Stage II.

 

ttt

TTT

 

That will be my next part to replace. Thanks.

 

I am currently troubleshooting the same problem and my mechanic told me that there's a good chance that it's the TPS sensor on the throttle body. The only problem is that my car got stage fright when I took it to him so he could hook his 0-scope up to it. I'm driving it until the problem comes back and we'll see if we can detect anything. I don't know how much it costs but I'm sure it can't be that bad. I hear they go bad when the car starts getting old anyways, so I guess if it doesn't work then it's just preventative maintenance right.

 

Alright...so I read all 10 pages of this when I started having the same problem on my M6 <low RPM missing in 1st under load>. I noticed the problem right after I did a TB Bypass, cleaned the K&N CAI, installed a 160* thermo, and power programmed. I opened her up, windexed the sensor that is in the intake elbow and my problem disappeared. I used a recharge kit on my filter, so I think it was just an extra oil problem.

My vote is for dirty <faulty> sensors causing the miss. At least it was free to fix. I know that everyone is having different problems...but start here. I love all of you on this website who have been teaching me how my car runs. <and how to run it better.>

~Matt

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Longhorn...driving a '94 Z-28 w/t-tops
-6 speed
-Borla Catback
-K&N CAI
-Hurst Short-Shifter
-Centerforce Dual-Friction Clutch
-Eibach Pro Springs
-SFCs
-TB Bypass
-Hypertech PP+
-160* Thermo
-Slow *** passenger window

 

If your battery or dist is greasy, there is a good chance you're not getting all the juice to the plugs.

I just recently started having the stumbling problem and after a week of looking I finally found that the #1 plug wire boot that attaches to the opti crap had expanded to almost twice the size of the connector. this was obviously due to oil saturation. The boot was just hanging there and it was easy to see where the spark was arching out.

Well I've ordered a new set of wires and I have a new backup opti. Now if the opti is in bad shape I'll replace it with the new wires which leads me to my question.... How can I prevent oil and whatever from getting on the boots and doing this again? Wrap it in saran wrap? Spray it with some kind of goop to prevent oil from hanging around? I'm open to ideas. I really believe this is what makes the opti go bad in the first place.

I really love my '93 Z/28 but I really hate tearing the engine down over just 1 plug boot. I won't mind this time however because I'm installing Borla headers while I'm under there. (Zoom zoom)

Mescaline

 

I have a 94 Z28 with the hesitation/miss problem.
Changed plugs, wires and cleaned injectors..nothing.
It cleared up after the technician replaced the O2 sensors..even though the computer scan never displayed any codes indicating that they were bad.
It's certainly worth a try.

 

Try cleaning the MAF sensor. I did that and it is running like it should be. I know some guys have 1993's, and i dont think that you have a MAF sensor, so i am stumped. But, i will keep everyone posted on how it is running.

 

My car did this for quite some time too. At first I thought it was my EGR valve so I replaced that and the problem went away. But then it came back. So I got looking around and I noticed that the wire with the boot connecting to the coil was arching. So I replaced that wire with a new one and now everything works great again! So try replacing the EGR vavle or check to see if your coil is fried.

 

health did you try pulling the cats? they were the problem on mine for about a half a year it hesitatated then it started to run hoter. i took off the entire y pipe and ran it open manifolds, it never ran or sounded better and yes my car would rev fine with no load. (your car uses allot less air and fuel to rev in netrual) with all the things you have tried it is defanatly worth the 5 min to pull your y pipe. i think a combo of a bad o2 sensor and tb cleaner did my cat in.

 

Far as i know this may help for nothing.... I read i think at least in all of these pages about seeing if the hose that was re-routed for the TB by pass was to close to the sensor in the intake elbow (IAT i think) well mine was like a half inch under it. So i rerouted it and to my surprise the hesitation i had was gone. i used to have the back fire problem but i fixed that up witha tune up (wires plugs coil, all the good stuff). So that problem was gone a long time ago somethin like a year i think.
any way back to what i am wonderin. IT was close to 90 degree's hear today and well with humidity, well it was hot..
i drove through town on my way home from work, turned on a road and tore into the 'ol Z and guess what when she got around 5500 actually to the shift point the ol girl back fired a few times (somethin like 3 times) what i want to know is, the car still runs great but what after moving the hose to keep heat soak from the sensor changed how everything was workin. What sensors adjust the timing (as in if there is a retard or advance) is it done by the comp. Could the sensor it self ( the one in the intake elbo be bad? I also believe the outside temperature has something to do with it being, when i drove it this morning it was like 78 and there were no problems...
just figured i would post what happened from relocating a hose, and see if any one has seen this or knows of any way that sensor could be bad. I have another sensor for that elbow and i am gonna give it a try..

j

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Silver, 95Z, A4, 3.23's, homemade CAI, TB bypass, MAF screen, boot converted to a 1LE style, borla catback, gutted cat, upgraded coil, HPP III, 160 thermo, 8.8 mm wires, numerous tires, and 9 spark plugs (guess dealership thought i didnt need that 8th one till later


Fast enough to beat an '01 gt

 

I'm sorry for bringing this post back from the dead but I wanna know if anyone has fixed their problem yet and what they did to fix it.

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Polo Green M6 Chrome ZR1 11's in back
RK Sport Headers, CSI WP, LT4 KM, Flowmaster Muffler, MSD 6A, Taylor Wires, 160 Stat
Catco hi flow cat, Cutout, K&N Filter Pack, Vortech Elbow
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