1999 Chevy Suburban runs rough

Check your fuel pressure again and volume. May be a defective fuel pump.

What should my fuel pressure be?

not sure which motor you have 5.0 and 5.7 should be 60-66 psi 4.8,5.3,6.0 and 7.4 are 55-62 psi If your pump had the Metri-pack 150 connector (shown below) it should have been replaced at the time the pump was done.

[quote:c820e67f8b="terescla"]Subject: Re: 99 Suburban runs rough
I don't have anything to check the pressure here right now. Someone told me it could be the MAF sensor. Do you think it could be that and if so where is it?
[/quote:c820e67f8b]

It is in the air duct going to the throttle body. Easy enough to test. Disconnect the harness from it and start the engine. If the engine starts...Relace it.

I'm going to replace it tomorrow for 140.00 and I'll let you know if it helps. Thanks again for the advice.

Before you do this.

Understand that I found this under a no-start condition procedure. There is no test that I could find for that sensor. That sensor may not be bad.

Before you buy it, I would rather have the code number you pulled and check the flow chart on it. I have had the testing information not be accurate in the past. Maybe the maf is bad and is one possible solution, but so would an air leak occuring after the sensor in the duct work or an intake gasket leak.

$140 is a pretty strong leap of faith. That connecter I mentioned earlier may also be playing into this.

If I was going to try a maf sensor I would probably stop at a junkyard and get one. If I went for a new one, I would ohm out the okd one and then ohm out the new one at the parts store before I was to buy it. These are not a terribly common thing on these in my experience.

I went and bought a new MAF and changed it in the parking lot and it made the suburban run worse so I went and got my old one back. I made a 6 hr trip after that and it still was sluggish when I first started to go and it jerked after climbing a hill. The service engine light was still on the whole time. Then yesterday I started the car and the service engine light was off but it still runs sluggish at the beginning then it runs fine. I'm running out of ideas. I have changed the gasket you where talking about and my problems with it running rough didn't start until I changed the fuel regulator( which fixed the starting problem). I don't know what if I have that connector you are talking about. I have a 5.7l engine. It doesn't look like anything I've seen so far.

Oh yea I didn't tell you that I replaced the fuel pump a couple of days ago (again) and that wasn't the problem either.

What codes numbers are listed in the pcm?

all we know is what the guy told us which was bank 1 and bank 2 lean. no number codes.

I guess would start looking for a vacuum leak with that much info. You can spray carb cleaner around the plenum and intake to see if an idle change happens. Propane will also work..unlit of course.