2003 3.8 grand prix enigine noise

[broncos]

Hi everyone how is it going?

I picked up a 03 grand prix special edition 3.8l, picked it up really cheap, just noticed a ticking sound when i rev it up real quick, but not when i rev slowly, one mecanic said it was the engine knocking, paid 900.00 for the car at an auction, no rust at all, about 110000 milles on it, changing my egr valve that went bad that was one of the codes i got, runs a litle better off then on, when i give it gas id just chokes, boggs, unless i let it pick up speed slowly, when i reach a hill forget about it its a disaster. found a 02 gtp engine with the same milleage for about 1200.00 and a year warranty if need so.

please let me know what u all think.

[cerick08GP]

Well, since you have no history with the car it could be a lot of things. Because you had a mechanic say it was knocking, I would change out the spark plugs ASAP. I would personally use Autolite 605s in your position.

If that doesn’t work I’d move on to the MAF and MAP sensors.

Good luck.

[broncos]

i unpluged the maf and it still ran the same, i know there was a recall on some type of plug harness or somthing pontiac told me but they have a place only next week. shouldnt the engine knock at all times instead of only when i rev it up in neutral fast, and also while im driving when its starts hesitating and bogging u might hear it.

[reveregtp]

if its ticking, then perhaps its an exhaust leak, on top of that you may have a clogged cat

id check those out as people tend to forget about them

[broncos]

if it was the engine knocking wouldnt it knock even if i reved it up slowly at a high rpm or not, it does that knocking noise only if i rev it quick.

[broncos]

if it was the engine knocking wouldn't it knock even if i reved it up slowly at a high rpm or not, it does that knocking noise only if i rev it quick.

[a98gtp4u]

throwing any codes?

[broncos]

throwing any codes?

tps sensor, o2 sensor in the back, egr valve.

changed egr no diff.. runs better unpluged.

fuel mileage is horrible, no knocking during normal driving, though no acceleration, no power cant pass anybody

I'm confused

[1LoudGrandPrix]

i would check the fuel filter and pump

[blueguy]

i would check the fuel filter and pump

How would that make a ticking sound?

[broncos]

If it is knocking then it will knock ALL the time.

This is a good example of rod knock. YouTube - MY 2002 WRX - Rod knock

that's the type of noise it makes only if i rev it up real fast at the end it makes that type of knock when i rev it up gradually up to 4000 rpm it wont do it, also when i try to give it gas hard when it bogs.
i'm changing the egr valve that was one of the codes, the other was tps sensor and 02 sensor in the back.

[broncos]

ok it makes a sound like that when you rev it hard up to 4000 on neutral, also in park i try to keep the revs up at 4000 and they start to drop, i changed the egr valve and it still runs better unpluged, the air filter was completely blocked like i have never seen before, it was so dirty that it looked like black tar, tried it without the filter sounds louder runs just a litle better, but still bogs, and holds back like something wont let it go. if i drive it smooth it goes ok, it knocks only when it starts to bog and i try to force it sometimes. if i rev it normaly until 4000 i wont knock

[Liquifire]

ok it makes a sound like that when you rev it hard up to 4000 on neutral, also in park i try to keep the revs up at 4000 and they start to drop, i changed the egr valve and it still runs better unpluged, the air filter was completely blocked like i have never seen before, it was so dirty that it looked like black tar, tried it without the filter sounds louder runs just a litle better, but still bogs, and holds back like something wont let it go. if i drive it smooth it goes ok, it knocks only when it starts to bog and i try to force it sometimes. if i rev it normaly until 4000 i wont knock

The rev limiter wont let it go any higher....the pcm has a set rpm threshold that it wont let you go over in park/neutral so that you dont blow your damn motor. Almost any newer vehicle has this if it is an auto. If you want to go above that RPM range, you will have to do it in gear.

[blueguy]

If it is knocking then it will knock ALL the time.

This is a good example of rod knock. YouTube - MY 2002 WRX - Rod knock

Could be a bad lifter too...that would be my bet...or a busted valve spring flying around in there and the rocker running all over the place. Take off the valve covers and unplug the ICM (the 7mm bolt in the front of the coil pack) then have someone crank it over and watch the rockers and see if they move up and down fine...if you notice one not moving right then that might be your issue on that particular rocker/valve...etc.

[blueguy]

I say broken flex plate then.

YouTube - 3800_flexplate

[broncos]

i read somewhere before about map or maf sensor cuting off power , it's like it wont accelerate when i try to push it only if i accelerate normally. when its holding back if i push hard on the gas it might knock.

[broncos]

and fuel millage is horrible, worse than when i used kill my z28 or mustang at all times.

[Sabrewings]

Clogged cat with probably a cracked flex plate.

[broncos]

whats a flex plate and where is it

[BillBoost37]

Don't worry about the flex plate. Please...

This thread is a train wreck of guessing IMO.

Can you get a vid of this knocking sound? That can help the diagnosis greatly.