Getting tuned up an running smooth again

[76elky]

Did plugs and wires a while back on my 00 tahoe Z71 with Vortec 5.7 an I'm still running a little rough on idle with possible miss fires but no check engine light.

Last week I replaced my ignition module...no difference.

thoughts for next steps are,
Accel super coil, rotor and cap, o2 sensors(180k miles an doesn't know if they've ever been replaced)



Any ideas.

I'm hoping replacing those parts will help a little with mileage too

 

[drakon543]

I haven't had an issue yet but judging from what ive read the coil can go bad on these and wont contain the spark proberly. As far as your cap and rotor as cheap as they are you probably should have just changed those when you did the plugs and wires. Check those out before you go after the O2 sensor. Ive actually had to just change the pipe before because removing the original o2 sensor ripped the threads right out of the bung. Other side note, unless your using performance wires, performance or overgapped plugs with a good cap and rotor your just wasting money on the accel coil. Without the extra gap in the plugs with better wires and cap and rotor the accel coil wont do anything better than the stock coil.

 

[SUBURBIAN]

Is the computer picking up the misfires?

 

[76elky]

no check engine light for misfire an the closest place wants $90 to hook the computer up an take a look.

An yes i would regap the plugs after changing the coil. As for the cap an rotor I have no idea why I didn't check or replace them when I did plugs an wires I know better than that. Guess I've just been off performance and on budget for a while

 

[SUBURBIAN]

Misfires won't set off the MIL until a certain threshold is reached. A scantool can show you misfire counts per cylinder, with the engine running. The only parts you should be using in the ignition system of this truck are OEM. An Accel coil is not going to help. Re-gapping plugs isn't going to help. If the plugs and wires you installed are not OEM/Delco, they could be part of your problem. If they aren't, promptly replace them with Delco parts. The cap and rotor you install should be OEM. I don't think replacing O2 sensor(s) will help right now.

 

[76elky]

Do you have any scantool suggestions. I've seen some that are bluetooth, wifi or usb

 

[SUBURBIAN]

I've only seen it done with a tech 2 or equivalent at my buddy's shop. This is the same device you said someone wanted $90 to plug in. If you were ready to buy a hot coil and some new sensors, which you probably don't need, maybe you could rethink paying the fee to hook up to this guy's computer. See if he'll let you throw some parts at it after diagnosis, then come back and see him for a freebie hookup in case it still isn't running right. Just an idea.

 

[76elky]

guess since i'm making the drive out to my parents this weekend I'll stop by my buddies shop and use his scanner

 

[SLCHOE]

Check the fuel trims. My guess is you are running at least +14% fuel correction on each bank. At your mileage/age, that intake manifold is probably leaking if it's never been done. Also the spider injector units have been updated to have actual injectors at each leg instead of just pintles and fuel pressure regulators are also know to leak at that mileage/age.

I also agree with SUBURBIAN and everything he has said.

 

[76elky]

I know a lot of maintenance was done 4 years ago by the previous owners a month before purchase. I really wish I had the list because I don't have $300+ to spare on replacing my spider at the moment. Will definitely be noting all that I find and be posting scan results