sc-driver

iTrader: (7)

1996 SC400

So I took my car out for a little bit of "fun" driving Sunday. It sat for a day while it rained and then I took my car out Tuesday to the store. I get to the parking lot and the car is idling very low. Around 500 rpm even though the engine is still cold. My safc2 says the airflow is around 1.2% (normal warm is 1.6%)

I park it and let it idle for a bit. It then starts shaking. No Check Engine Light's. Below 1500rpm and the car feels very sluggish, above 2500rpm and it's more or less normal. It also starts up fine too. I get back home and kept it at idle. The rpm's went all the way down to 200!!

3 CEL's came up: (in this order)
p0171 System Too Lean (Bank 1)
p0133 Oxygen Sensor Circuit Slow Response (Bank1, Sensor1)
p0153 Oxygen Sensor Circuit Slow Response (Bank2, Sensor1)


I've done some extensive searching and p0133 along with p0153 usually means contaminated fuel. My tank was low so I filled it up and bought some seafoam.

I've seafoamed the car through the brake booster and in the gas tank. Reset the codes and now ONLY p0171 comes up. I've reset the codes a couple of times and it only comes on at light throttle below 1500rpm. But the car drives ALOT better after the seafoaming and filling up.

So far....
I've cleaned the MAF with Hotwire MAF cleaner,
looked for vacuum leaks with brake cleaner,
looked for boost leaks with soapy water,
had an exhaust shop check for leaks
seafoam through brake booster and in tank,
new spark plug wires 3000 miles ago,
new plugs 20,000 miles ago,
new fuel filter 3000 miles ago,
cleaned air filter 500 miles ago,


So my question is, do you think my injectors are dirty because of bad gas?
I've felt the injectors and the injectors on cylinder 1,3,5 on bank 1 (driver's side) feel "weak to the touch"

Any input will greatly be appreciated,

Thanks,
David

FINAL EDIT...*SOLVED!*...

It turns out that moisture, and some water got into the gas tank on Monday and when I went out to drive on Tuesday, the water in the gas tank quickly corroded the fuel injectors. This is only possible since my gas tank was just about empty.

Seafoamed through the brake booster like 4 times and put 2 cans of it in the gas tank. Problem went away after finishing entire tank. Never came back!

Lexusdad

iTrader: (1)

My Daughters SC3 is doing the EXACT same thing. I took it for a sefety inspection on Saturday. Topped off her tank for her, and later that evening she complained of it hesitating (sp) and shaking while driving over a steep overpass in our area (there are no hills in Coastal Texas). Have not pulled codes (don't have a reader). In three days she has ran down to a half a tank, so I fefilled and added seafoam. A little better, but still very sluggish. Only remedy I can think of is to drain tank, or syphon out all you can and then refill. Station I filled up at is very high volume, no delivery was in progress when I was filling tank.

Car was running (and had been running) flawless for the past 6 months (since waterpump change) and then fuel up and it starts running like crap. That was the only thing added to the mix. Had fuel filter changed yesterday, it was dirty, but did not shake out anything that was alarming.

This is the absolute first time ever, in my 30+ years of driving of getting suspect fuel.....at least that is what I hope it is.

Jim

sc-driver

iTrader: (7)

Update:

The more I fuel up, the better the car is getting. Feels more responsive, airflow is slightly increasing (oscillates between 1.3% and 1.4% as opposed to 1.1%). The car PULLS at high rpm.

At this point, should I get the fuel injectors cleaned with an on-car cleaning system? My check engine light is still on.

Lexusdad, are you still having the same problems? Did syphoning the tank help?

David

718murdoc

What gas do guys use ?

sc-driver

iTrader: (7)

Shell Premium (91 octane highest here)

Lexusdad

iTrader: (1)

Sorry for the late reply. My problem was a heater hose leak at the rear of the block. There was a split in the hose, and water was running into the back spark plug valley (SC300). This caused a misfire of one or both of the back plugs (5 or 6). Cleaned everything up, new heater hose, new plugs and wires, and it is running like a top.

I rotate which gas I run in the car. I have Exxon, Shell, Chevron, Valero and Conoco/Phillips very close. All 93 octane, this particular tank was Valero, but had NO bearing on the problem. I run a can of seafoam about every fourth or fifth tank, this is my daughters car.

Jim

manchesi

i would try the 12 volt fuel mod mine was a low idle 400 rpm now its 110% better and verry responsive i have a 5speed with 96k

sc-driver

iTrader: (7)

I'm pretty sure the fuel pump ecu is fine. The check engine light I have doesn't correlate with a failing fuel pump ecu.
Besides, I'd have to tear out the rear seats to get to it and rewire it. I cant just do the paper clip diagnostic shortcut since I have a 96 (obdII).

Currently, the cars been driving just like before. The only thing being that the CEL is still on.

Thanks for the response though!