2002 Oldsmobile Alero Power hesitation

TOWCAR

MEMBER
2002 OLDSMOBILE ALERO
6 CYL
2WD
AUTOMATIC
59,000 MILES

Hi guys, first time lurker here.

My car recently started having issue, where at lower speed the car will lose power (the engine still revs), after a while the car would gain more power again (35mph +). Described the symptom to my co-worker (he's ASE certified, but he's currently a maintenance supervisor at my place and he's always busy) and he scanned with his meter (don't know what model) and it didn't give any code. He suggested me to take the car to a transmission shop (it did seemed like a shifting issue to me) and have it checked.

At Aamco the guys checked it out and said it's a not a problem with the transmission but with the Catalytic Converter, the tech took it off and the car ran fine. They said the cat is plugged and it stinks when he took it off. As my cat is still under warranty (8 years, 80k Mi). They didn't charge me and I took it to the dealer.

Dealer called back saying the problem isn't with the Cat, but they did get a random misfire code and a code for the EGR valve. They wanted to do a fuel induction service, new spark plugs, wire, and replace the EGR valve, $899 + tax and all the fees of course.
I have my co-worker called them and explain to what the guys at Aamco find but the dealer insisted that they problem isn't with the Cat and that they have better machinary for the diagnosis of the problem.

I've had service twice before at this dealer due to bad gas (or so they say) where they did the fuel induction service, spark plugs, the whole deal, and drained the gas tank and cleaned it. They also mentioned each time when I was paying that they also replaced the fuel pump under warranty, even though they're not supposed to do. The last time I was there was 1.5 years ago and my spark plugs and wire looked brand new to my co-worker.

I don't know who to believe here, something tells me that the dealer is kinda fishy with the fuel pump replacement (may be that's the real culpit and they're charging me all the extra work for nothing?).

I can always take it to another shop but it'd be another $100 just to check it. What do you guys think I should do? My co-worker did say may be he can bang on the cat for me and put it back where it won't be plugged anymore, but I think also render the cat useless. Or risk taking it to another dealer for the chance they will think it's the Cat?

Help please.

1 Reply

KNOWYOURAUTO

MECHANIC
113 POSTS

Towcar,

Fortunately your cars catalytic converter is covered under a federal emissions warranty. If it is bad the manufacturer is REQUIRED to replace it at no cost.

Unfortunately another component may have caused the converter to fail and the dealer may not be required to replace it at no cost. Some key points you will need to know about your circumstances.

EGR related issues. A plugged catalytic converter is usually symptomatic of a rich running system that allowed too much unburned fuel to reach the converters "honeycomb" element and clogged it. This is similar to what happens in your frying pan; after cooking there is a black residue left over.
The EGR system only interferes with the vehicle in the way of making it stumble or stall at very low speeds and mostly at idle. Once the vehicle is moving about 10mph or faster and the throttle opens partly there is enough air entering the system to compensate for a stuck open valve. What this means: the condition you are describing cannot be an EGR problem because your engine would not hesitate once the vehicle was moving at the speeds you described.

Catalytic converters: A back pressure test can be performed to verify a plugged system by removing the o2 sensor in front of the converter. Try asking the dealership what this test showed, specifically. "It was fine" means it may not have been checked. Any reading over 1" of pressure is too high and an inspection should be performed by removing the " �Cat'. I have performed the same test Aamco did, by removing the pipe to the " �cat', and then driving to verify the fix.

I would agree that you likely have a failed converter, but be wary about another component like a stuck open EGR valve that may have caused the failure, and the dealer not covering the repair, becoming more expensive.

BTW you could likely forgo the spark plugs and wires at your mileage since you stated it was done previously. The fuel induction service does a poor job at cleaning EGR passages, exhaust valve and port buildup, where any carbon may have settled from the clogged exhaust and is not recommended either. Again, you are very likely to hear from the dealer they will not warranty any items if you don't also replace X, Y and Z at the same time. The Better Business Bureau may provide some relief if this comes up.

Good luck,

KnowYourAuto