Yikes! My SES light has been coming on and off lately, but it had been doing that since I get the car so I didn't worry, then stuff started going wrong. First, the car died while backing it up during a warm start (car sat a bit, but didn't comletely cool down). It smelled of gas a bit, but then it started after a bit of cranking... weird, did it one night then done.

Now today, its raining like crazy and I am driving along, car is surging, or has a miss or something, not sure what is going on, but power is not constant for sure, RPMs are also jumping a bit... SES light comes on and I figure I need to get this fixed.

So we use a code puller and here are the codes...

13: Oxygen sensor reports lean
35: IAC idle problems, either + or - 125 RPMS of desired by computer at idle
44: Lean due to air leak from gaskets, bad oygen sensor or fuel pump....

Now, what would you guys make of these three codes being tossed by the computer? Is my fuel pump going? Fuel filter clogged?

This doesn't appear to happen when I have a full tank of gas, but when it gets below about half full it doesn't seem to like it.. but I am not 100% sure if that is constant.

Thanks a ton!
Douglas

P.S. Car is a 1990 Firebird V-6 3.1 AT

 

ARS,

Look for an intake leak. With all the DTCs reporting a lean problem, you probably truly are lean instead of having a sensor glitch.

Don't overlook the PCV and power brake booster. You can eliminate those easily by unpplugging and capping the vacuum lines, but remember the car is a lot harder to stop with no power brake assist.

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Later,
Vader
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Justice and Freedom will Prevail

 

Doug, is your idle noticeably higher than normal? If so, that definitely indicates a lean condition usually due to a vacuum leak.

When you pull an SES code, the ECM goes into Fail Safe Mode and will use "pre-defined" settings to get the engine to run "reasonably well", so you can drive it to the shop and get fixed. Limp Mode basically allows you to pull over to the side of the road...not much more.

It is not too uncommon for one failed part to throw other codes (as the ECM will adjust settings to keep the engine running). But neither a "weak O2 Sensor" or a "weak fuel pump" will cause the engine's idle to increase noticeably. A vacuum leak will.

To eliminate the fuel pump, check the fuel pressure of your engine with the engine running (but no vacuum line connected).

When Fuel Pumps go, they tend to just fail (ie. you go to start the engine and it just cranks and cranks). But I am sure that a few have experienced a "weak fuel" pump, I just haven't met any. But check the fuel pressure with the engine running (for a period of time) to eliminate it. But ultimately, I am inclined to go with Jeff's suggestion especially if your idle speed seems to have noticeably increased.

Guess you don't have a scan tool eh? They can be useful to track these problems down, but not necessary as you can diagnose this with "mechanical methods".

[This message has been edited by Glenn91L98GTA (edited September 27, 2001).]

 

The idle is not higher then normal like if there were a vaccume leak. The idle is a little rough and the car wants to die sometimes at idle (and did last night twice while trying to back up) but the idle isn't high.

 

Do a test of the fuel pressure and see if you can find someone with a scan tool. If I was going to the Coast this weekend, I would meet up with you. But I have a heavy work commitment this weekend and I am suppose to meet someone else next weekend.

Guess you could come to Kamloops.