Chesty for President

iTrader: (2)

I got an SES light sometimes flashes sometimes not. Almost doesnt want to idle like it has to catch up for about 15 seconds then its ok. Car doesnt smoke until i get on it then lots of black smoke. Ive replaced plugs, wires, factory FPR, O2's are both new, new fuel filter, cleaned MAF with MAF cleaner, I have not checked for vacuum leaks yet or ran in the dark to check for arcing over but will tonight. I have an auto x-ray and I can clear the code once i start the car and it wont come back until i start the car again but i clear it every time i drive it. Mods are in sig. Lately there is a wierd noise coming from the left front side of the car that ive never heard nor can i really explain. The noise changes with engine RPM as the engine revs it gets faster but doesnt sound like an exhaust leak almost like something rubbing. The SES light will flash once every few weeks and its still the P0300 code, once cleared it doesnt come back for a few weeks. Car is running rediculously rich and using alot of fuel. Just my luck when im trying to sell it all this stuff happens but i want to fix it correctly before i sell it. Any help or advice is welcome and greatly appretiated...Semper Fi

LS6427

iTrader: (2)

Bent valve maybe. It will cause flashing ses, which is a multiple misfire code. Maybe you have more than one bent valve. Have you romped it hard lately, right before this stuff started. Maybe bounced off the rev limiter?

Also, one of the two new 02 sensor(s) can be a dud. The running rich points to bad 02 sensor(s). Get a scan to see how they are switching while the engine is running. They can also cause multiple misfires.

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Chesty for President

iTrader: (2)

will do brother theres a place on base that will scan it but its like 65.00 does that sound about right. I never really get on the car hard or even come close to over revving it, it has some pretty beefy comp cams pushrods. Im not even sure why I put all the money into it i drive like a 90 year old man. I really appretiate the help im gonna pull the left valve cover this weekend just to check things out ive read a few other posts i figure it cant hurt im just afraid i mite find something. Ive got a fan that is squeaky but im pretty sure they dont change speed with engine rpm

sjsingle1

iTrader: (1)

does sound like bad O2s......

98_Formula

iTrader: (15)

i had similar issues that ended up being caused by an exhaust leak before the o2's... i had headers with the slip on collectors though... once i got those welded up I haven't had any problems. it was giving completely wrong readings to my o2's, which causes all kinds problems

LS6427

iTrader: (2)

$65 is alot to me, but around here scans are free at alot of places. Maybe try calling a few GM dealerships and ask if they can help you out with a scan because your low on funds. Believe it or not, some of them actually will help you out. After all, it will take 1 minute to scan it to tell you how the 02 sensors are working. Also, regular mechanic shops might do it for free too, but they have to have an OBDII scanner.

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Chesty for President

iTrader: (2)

I thought maybe an exhaust leak also its kinda what it sounds like but the damn car is so loud its tough to narrow down...Cant thank yall enough for all the help and advice with this I leave to deploy in a few weeks and i cant let it sit broken itll **** with my head the whole time im gone. this thing is murdering my head...ill post whatever end up fixing it in a few days also ill record the sound its making maybe itll help someone else down the road...

I8ASaleen

iTrader: (9)

Does your exhaust setup have any flanges or places that are prone to leak, especially before the O2 sensors? I wouldn't think that would be the problem since you have LT's (are the O2's in the longtubes?)

Chesty for President

iTrader: (2)

No Sir the O2's are in the Y pipe, I got what sounds like a small exhaust leak or something that changes with engine RPM or a broken valve spring on the drivers side, if its an exhaust leak its very mild. im gonna check it out in the morning before i pull my valve cover. I have had to tighten my back header bolt a few times though from it leaking previously but they are all tight right now. doesnt mean the gasket aint bad though

I8ASaleen

iTrader: (9)

Yea a small exhaust leak would sound like a moderate ticking noise, you can use an auto stethoscope to pinpoint it if you have to.

FiredUpZ28

That 65 bucks is going to tell you what the actual problem is - the free scan just gives you codes.

01ssreda4

iTrader: (96)

unplug the maf and run the car and see if it clears up. That shitty of gas mileage could be a bad maf. I know from experience

Chesty for President

iTrader: (2)

ok i worked on it a little at the hobbyshop and i pulled the valve covers and rotated the motor by hand and all the rockers were tight and good to go. no exhaust leaks.."my o2 sensors are in my headers by the way" I DID NOT get a chance to check the fuel pressure but will tomorrow...plugs look sooty. I had a guy use a stethescope and he said he heard something on the passenger side but was unsure of what it was i can hear it with the valve cover on. I replaced the o2 sensors and still no change...The damn diagnostic machine was broken...
It sounds like it is "loading up" really bad like its floodingg out once i rev it and clear it out its ok...i really need to check the fuel pressure. this thing is wrecking my head. ill try and unplug the MAF and see if that does anything i got a pm suggesting that. im lost as hell FTC

Chesty for President

iTrader: (2)

Kinda found my mileage issue i never know it would drop so damn bad driving it short distances like that but i guess that was it, i took it out on the road for an hour or so and guess what the damn mileage was back...im a ratard. No cracked valve springs i still dont know what the ticking is i think its an exhaust leak but itll have to check it in 7 months. Also i never got a chance to check my fuel pressure at the rails...Thanks all of yall for the advice on this and when i get back from Korea ill def be getting back to wrenching on my Bird...Semper Fi

LS6427

iTrader: (2)

Kinda found it......what was it?

If that is an exhaust leak, even a tiny little pinhole leak, it will throw your 02 sensor(s) off on that side and you will run pig rich. Pig rich where your gas mileage will go down the tubes.
I've had this happen, my mileage went completely to ****, I could almost watch my gas needle dropping, it was terrible. Had a couple little holes welded and BAM, perfect again.

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01ssreda4

iTrader: (96)

Maf maf maf