I need your guys help

[Lee'S 1997 Z28]

Hi Guys!

I have a 1997 Z28 and it pop's in the exhaust when idling. It don't pop in the intake.

It will do this from idle to 1900RPM's. It puff's a little black smoke every now and then when it pop's. It will miss a little at a red light but not when I pull out and give it gas.

It don't hesitate in the upper RPM's and has plenty of power.

It did have a water pump leak last year and I replaced the pump.
I have replaced plugs and wires, EGR Valve, Checked the Fuel Pressure keyon Engine off 47Psi Idling 39 to 40 Psi.

What do you think it could be Fuel injectors, opti, ignition coil, ICM, O2 Sensors?

No Check Engine Light!

I am Puzzled!?

Thanks Lee!

[Formulaboy95]

Have someone scan it first. AutoZone should do it for free. Also check the spark plug wires, from spark plugs into the opti. A small leak from the waterpump can get under the old wire boot at the opti, happened to me, and only affected 1 cylinder. But, sounds like opti to me. Could be the distributor section of the opti too, mine was horrible. I got no codes when scanned mine, because optical sensor for the opti was ok. But I am definately leaning towards opti.... anyone else agree/disagree?

[Lee'S 1997 Z28]

I scanned it myself because I work for AutoZone. No Codes were found.

[Joe 1320]

How many miles since plugs/ wires? It's most likely an ignition problem. Could be wires/plugs or opti. Since the water pump leaked, I would suspect the opti/wire terminals. I would first pull each plug wire boot from the opti and check for corrosion. That could be cleaned and put back together for $0. If it's not the plugs and wires, you know what is left.

[Lee'S 1997 Z28]

Plugs and wires done about 3week ago.

What would O2 Sensors act like if they were bad. Are they hard to get out because I scared of busting my manifolds trying to get them out.


My car has 76k miles on it!

[elvis89fb]

is it backfireing or popping

[LeeS97Z28]

Sorry it took so long to get back to ya!

It just pop's it don't backfire. It misses when it does this.

Thanks Lee!

[elvis89fb]

might be avery small leak in the exhaust causeing some air to get in there and helping to ignite unburned fuel

[Torque]

I would definitely bet on the Opti. I probably would not worry about it until it gets worse and you actually have to replace it. I agree that you probably got water in it when replacing the water pump.

No offense, but the Autozone Code scanner su*ks. I just bought one my experience is that the only time it will pick up a code is when your check engine light comes on. This means that you can't diagnose problems like what you are experiencing unless you have a much more expensive scanner such as those that will record real time data which you would have to interpret on your own.

You could hook up with a good scanner to double check or go ahead and do the opti.

Good luck!

[LeeS97Z28]

Thanks guys I appreciate your help!

The popping is getting worse now I noticed this last night. It getting to the point of stumbling so its going quick.

Would this cause my car to be hard to start by requiring extended cranking to start?????????

Thanks Lee!

[Joe 1320]

Originally posted by LeeS97Z28
Thanks guys I appreciate your help!

The popping is getting worse now I noticed this last night. It getting to the point of stumbling so its going quick.

Would this cause my car to be hard to start by requiring extended cranking to start?????????

Thanks Lee!

Yup. I'll bet it is a failure of the cap and rotor portion of the optispark.