parkers Z28

car has a miss / backfire / shooting / popping ???? I would like to get some advice before I take my car to the shop...... I'm not able to scan for codes but
the enginelight is NOT ON ...the backfire/ missfire shows up under wide open throttle the most and sometimes there is a stumble in normal driving conditions .. the backfire / missfire does NOT
show up when I'm in the driveway only when I'm on the road

shoebox

A scan would be helpful. Some of the ignition and opti codes don't light the CEL. Kinda sounds like opti, though.

parkers Z28

Shoot !!!! I have seen on here there like a ticking time bomb ....
I know a guy that that has a scanner he is on the way over here to see if he can pull the codes if any
I will let you know what he finds ... there just number & letters to me Lol

Injuneer

You should add the year of your car to your signature.

parkers Z28

all this time and I thought it was in there Lol ....its a 94 I change the mileage every thousand miles
Mike checked the car for codes with a auto xray none (0) were found ???
in the history the only thing that showed up was EGR ?? I have seen on here that some of these
scan tools don't work on a 94 Z28 not sure if this is one of them ???
there should be some codes right ???? in the drive way with my foot on the brake car in gear I can Not make the car skip / stumble ... while driving down the road if gas it pretty good it will bust out threw
the intake and the exhaust. if I back out of the gas it will clear up sometimes it will stumble
for a while and clear up
could it be fuel pressure ???? I all so put in a bottle of fuel system cleaner / stabilizer about 80. miles ago not to fix anything it was running fine at that time doesn't see a lot of highway

Injuneer

94 has no codes for misfires or high voltage side of the ignition, so a stumble doesn't mandate codes. The Auto X-Ray generally works fine,on the 94 as long as it's an OBD-1 scanner. It's breaking down under load. You can't replicate that sitting in the driveway. Spark or fuel.

parkers Z28

Drove the car down to the boat dock same results popping threw the intake backfire threw
the exhaust and then runs fine as long as I stay out of the gas ....

the auto xray had two different plugins plugged right up asked for some of the vin#s
I seen the sticky for the free scan on here.. not much with computers can't find the gas
pedal or the trigger... My sister and her kids or coming over tomorrow to ride the jet ski and
boat. I'm going to have to get the 14 year old girl to help me work on my car I'm
sure she knows how to down load stuff.. Let you Know what I find

parkers Z28

I just looked under the hood nothing grounding out and sparking on anything
I did notice some water stain build up on top of the intake beside one of the opti harness
plugins ??? going to clean the connector maybe I will get lucky ???

parkers Z28

I didn't have time to work on the car today as if I really know what I'm doing anyway
Going to the shop on Monday or Tuesday ?? as soon as they can take a look at it
I was looking at some pictures on opti installation looks like now would be a good time
to swap out the cam shaft ..... Any recommendations on a opti I did a search on here
and it looks like a toss up mixed reviews

slick1hunting

most people suggest delphi or ac delco. Online is usually far cheaper. Rock auto is usually a good place to look for parts. Delphi is usually about $75ish cheaper


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parkers Z28

Stopped by the dealership today and talked to the service manger .. he said that he could
take a look at it tomorrow $101 for the diagnostic fee $374 labor fee .... I asked him about
doing the cam swap and he hit a few buttons on the computer and laughed and then he said
$ 1274 dollars for labor ... I really need to start working on this thing myself
is changing the opti a pain in the *ss

slick1hunting

Changing the opti is probably more time consuming than anything. Definately a few things that need to pay proper attention too but most of it is just removing parts to get to it. I would be shoebox cam replacement instructions probably has the basic instructions for opti replacement as well. While you are there changing the seals in timing cover is probably a good idea.(I would get a couple extra seals because they are fragile(waterpump drive seal). If the waterpump has alot of miles its a good time to replace it too. Getting the aldl cable and using the free software on a laptop would still be a good idea(and for $60ish a good investment). It sounds as if its not fully diagnosed as the opti yet or did you get your codes(and what were they). The sticky on the top may have a few good tests you can try too before letting the shop have it. Do you know what opti is on it or how long? (Sorry if you posted already I have read everything just been a few days as I have been following your post.) Did you check the fuel pressure yet? You could take that sucker on your windsheild and watch pressure. Haha now I really cant remember all of your post and may be adding a different one. If no codes about the opti signal are present I might start looking at plugs-wires. Coil and icm. Ive seen people who had a bad coil wire replace way too much just to find it was a wire. Sorry for the long post but sounds like you have big choices and possibly a big expense in front of you.


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parkers Z28

Dealership said...... " road test to verify concern . Engine skipping under a load check plugs ,wires and coil . spark plug wires breaking down under a load . need to perform full tune up with spark plug wires. Cap and rotor original . may need to replaced " wrote just like that on the bill

The guy pretty much said that I need to replace everything parts & labor $1,744 for a tune up W.T.F
are they crazy ? I gave them $ 101.75 to tell me something is breaking down under a load
I already new that.....they could not pinpoint what is causing the issue are the service manger
is trying to rip me off I have looked overt what he wrote down on the bill and it doesn't make
any since. what do they mean " " cap and rotor original may need to be replace ... ""

slick1hunting

I am sure you are upset(I would be) did they scan for codes and were any present? If not perhaps they will because that may help your repair. The cap and rotor are a maintainance item and it is possible that alone could get you going. New wires can also make a world of difference. Their prices are way off or their shop rate is double what my local dealer was. The ac delco wires are very spendy from dealer and I am sure the cap and rotor are too. My guess is they have you at over 5 hours labor right there and $300 parts and this doesnt even include the sparkplugs and coolant. If it were mine I would do the plugs and wires and see what that did(doing it myself). If that cleared it up I still may do cap and rotor but would be leary of cap and rotor without knowing opti is still working good. I would get all the info out of them you can like did they check fuel pressure(if so what was it as well as anything when they had it hooked up for diagnostics. Perhaps they will see they half @ssed you or you will see they just dont care or perhaps you just need more communication with them.

parkers Z28

After reading this a few more times it looks like the guy that was working
on the car suggested plugs & wires and the service manger suggested that I
replace everything. going back to talk to the guy that was working on my car
let you know what he said ...