Silverado Help.................Im stumped!

[walleye29us]

1997 chev. Silverado. 5.7 liter 4x4. 165,000 miles. My truck was running rough at idle and engine light was on. So i bring it in to the shop. They replaced the intake gasket,plugs,plug wires,distributer cap and rotor,....Still doing the same thing.ROUGH IDLE. Go back then they replace something called a SPIDER or SPIDER WIRES?..Still running rough at idle. Go back they replace ignition coil and i told them to throw in a new battery too. SAME CONDITION! grrr! I need you guys to PLEASE give me your suggestions what to do now? HELP.

[Jeremy airjer W]

Is the check engine light still on?

What where the codes?

I'm thinking that since they replaced the intake there might have been a lean code. This could have been set falsely by a bad O2 sensor. Scan tool data would show the sensor either stuck rick (which could cause lean codes) or stuck lean (which would cause rich codes). Either way unplugging the upstream sensors will default the values to center or about .5 volts if everything is working. If the idle returns to normal than your on the right track. You just need to figure out which sensor is bad.

Just a thought without data to support it.

[walleye29us]

Thanks for your input Jer. Yes the light comes back on every time soon after i have something done. I had autozone pull the codes for me. Code was P0430.

[RumRiverRat]

P0430

P0430 - Catalyst System Efficiency Below Threshold Bank 2

Possible causes

- Three way catalyst converter Bank 2

- Exhaust tube

- Intake air leaks

- Fuel injectors may be faulty

- Fuel injector leaks

- Spark plugs may be faulty

- Improper ignition timing

- Engine Control Module (ECM)

Read more: http://engine-codes.com/p0430.html#ixzz36p7jaLz0

[delcecchi]

1997 chev. Silverado. 5.7 liter 4x4. 165,000 miles. My truck was running rough at idle and engine light was on. So i bring it in to the shop. They replaced the intake gasket,plugs,plug wires,distributer cap and rotor,....Still doing the same thing.ROUGH IDLE. Go back then they replace something called a SPIDER or SPIDER WIRES?..Still running rough at idle. Go back they replace ignition coil and i told them to throw in a new battery too. SAME CONDITION! grrr! I need you guys to PLEASE give me your suggestions what to do now? HELP.

Sounds like they are "easter egging" the problem. Who are these guys? Dealer, independent, chain?

[Jeremy airjer W]

Typically cat in efficiency codes don't cause drive ability issues. The problem is on bank two so we could look at misfire data (pretty sure we can do that with a scan tool for this year), fuel trims, and O2 data on that bank and should be able to see something not right. If all the misfires are are on the bank 2 cylinders and the bank one cylinders are o.k. Than I would go for the cat being partially plugged. Again the Upstream O2 sensors would have to prove that they are working before pulling the trigger on the cats.

The other thing that is plausible is one of the cylinders is getting weak, possible on bank 2. A compression test would shed some light on this theory.

[walleye29us]

Are them O2 sensors hard to replace?

[18 inch Crappie]

Are them O2 sensors hard to replace?

At this point I would take it to someone that knows what there doing, throwing parts at is not going to fix it right. And that place you had the work done get your money back, because they never fixed the problem but still took your money.

[walleye29us]

They wont give me my money back. They did alot of work on it. Does anyone have any tips on changing out the o2 sensors? I cant afford to bring it somewhere else and would like to try some things on my own.

[walleye29us]

Well i did a little searching online. Looks like its best to get the special socket with the slot in it to go over the wires. I just wished i knew what o2 sensor to start with.////Another question. Are them 80 dollar code readers at autozone worth getting. It looks like then i could clear the code after any o2 sensor replacement and see if the light comes back on, or the rough idle clears up. Thoughts?

[Jeremy airjer W]

Once again, unplugging the upstream O2 sensors one at a time will restore there values to a default number. If the idle improves than that sensor may be the culprit. It is very easy to unplug and check.

The $80 code readers are just that. Code readers, code clearers. They may have limited OBD Data.

[walleye29us]

Thanks Jer. Upstream means engine side of the CAT?

[Jeremy airjer W]

Yup, before the cat is upstream. After the cat is downstream. Upstream helps determine fuel values. Down stream monitors cat efficiency and will generally not contribute to drive ability issues.

The drivers side connector should be up on the transmission right above the linkage and PRNDL switch. The passenger side will be on top of the frame right behind the right front wheel.

[walleye29us]

Thank you very much Jer!

[walleye29us]

Hey Jer. I have new info. Just had the codes scanned since i havent since the last time it was reset. 2 Codes,,P0300,,AND,,Po306. With this new info, what you thinking now? Still possible o2 sensor, or something else?

[Jeremy airjer W]

Compression test on the number six cylinder.

P0306 is a misfire code for the number 6 cylinder.

P0300 is a multiple cylinder misfire.

Since the plugs, wires, cap, rotor, coil, and CPI unit have been replaced with no resolution the next step (which in this cause should have been one of the first steps) is to see if the problem is mechanical...low compression. A quick compression test will give you the answer you need.

[walleye29us]

Thank you sir!

[Gus]

I had a similar issue on a 98 tahoe when they replaced the intake gasket. It actually ran worse than before.

The "spider" thing, whatever it's really called, I think my mechanic called it an octopus looking part, was not put back in the right order.

It could be this was overlooked in the replacement?

Sort of like putting the plug wires in the wrong plugs.