'99 Alero, acceleration & RPM problems

Looked back 5 or so pages and didn't see much on this.

My '99 Alero, 3.4L V6 has been acting up a little for a while now, and last Friday it was very bad on my ride home from work. The car has had a hard time accelerating when it changes gears, typically with a spike in RPMs up to the high 2K's. Last friday it basically did this constantly though, my whole ride home until the very end when it came out of it. It wouldn't accelerate well at all.

I took it in to the local dealer garage and had them look at it. The mechanic said that at least initially the problem is caused by the aftermarket cold air intake, and that the mass air flow sensor is shot. The estimate was over $500.

Bit of background:
I bought the car about four years ago for $2800 w/ 46,000 miles on it. I've driven it a hell of a lot and its now around 110,000. The only other money I put into it was regular maintenance, a set of tires when I first got it ($300) another set just recently ($300 again) and the lower intake manifold replacement (~$500) that I was just out of the recall date on (just had it done about two months ago).

So all total I've only put about $3900 into the car and gotten over 60K miles out of it. I think its given me my money's worth, but at this point I'm not looking to throw good money after bad and keep having work done to it.

So my question:
Is the problem likely the MAF and nothing more? How hard would it be for me to replace it myself? I'm somewhat mechanically inclined, changed the plugs, brakes, and wheel rotors before, done more alternators than I care to reflect on. I've never dealt with air, exhaust, or coolant systems though. Basically I can unbolt a part, pull it out, and put the replacement in right but more than that and I'm not really game.

Is it reasonable for me to think that replacing the MAF will do it, and if so are there any good tutorials on replacing the MAF? Look forward to and appreciate any help.

If it is the MAF sensor buy it yourself anjd forget about the mechanic doing it. Too much $$$. Easy to replace DIY. Another issue that may cause your problem is a bad intake air temperature sensor (IAT) or a bad electrical connector to it. It will cause the tranny to shift erratically. GM has a service bulletin (TSB) on the issue.

There are some good step by step instructions in the Grand Am forum for replacing the MAF. It has step by step instructions with pictures that should help you out a lot. Do it yourself! Very easy and more than worth it.

Just got looking to see what the MAF actually was and had a "DOH!" moment. I took it off once before when my aftermarket cold air intake was being a little fussy fitting back on after a cleaning. ;P

Already ordered a replacement, found it for $80 new, should be here in a few days and will have it replaced in no time I'm sure. Much thanks for the help, and heads up on the TSB, going to check into that as well.

If it was the MAF sensor you probably would have a DTC set. Same with the EGR valve. Buy a can of spray MAF cleaner and clean the screen. Remove the EGR valve and spray it with EGR cleaner. Don't use EGR spray on your MAF.

Your description of the lack of acceleration and performance is a classic issue with the 3.4L engines. GM issued a TSB for the catalytic converter for models with the 3.4l engine but DID NOT include the Alero. The issue is a clogged cat conv. which drastically affects acceleration and performance. The warranty was extended to 10 years and 100,000 miles for the cat conv. Unfortunately it does not include the Alero.

The good news (sort of) is that you can get a 49 state (not California of course, Cali compliant is $202.00) cat conv. from Murry's Auto, Advance Auto, etc. for $79.00 and it's easy to install if you can get under the car. Dealers typically want $600 to replace the cat conv. Cut out of cat conv close to the welds, insert new cat conv and assemble with new sleeves and pipe clamps.

You can test your cat conv to be sure it is not clogged by removing the hot (upstream O2 sensor) and inserting a pressure guage. Run the engine at 2,000 rpm. The pressure should not be more than 2 psi. Do the same for the cold (after cat conv) O2 sendor and the pressure should be the same or less 2 psi. If the upstream pressure is higher than the downstream pressure and above 2 psi you have a clogged cat conv.

also reference post #190 on multi-cylider misfire for more help on this topic

I would change the Trans.Filter and Trans oil;
Sounds to me like it is Slipping;
That car does not have a Dipstick,There is a Plug on the Pass side of Trans ; I Refilled mine with a large plastic Syringe with a Hose from Farm store. Then repeated process at the Fwd cooling line until I got the Black out of the oil;