Bogs down uphill
 

Maybe someone to can help me here...

2001 alero 3400 auto trans

2 weeks ago after getting gas i notice about a mile down the road the car was lacking power. If you step on the gas it almost feels like the car is out gas and barely moves. I put seafoam and premium gas in it with the same outcome.

This weekend a buddy of mine came over with a cat tester and a tech2 scanner to help me diagnose this issue.

The cat pressure is 3-4 where it should be, i changed the fuel filter as it was pretty clogged. Changed the top o2, coils, icm and cleaned the maf. I took a gas sample and theres visually nothing wrong with the gas. We checked the fuel pressure at idle.. it was 50 + or - 1 then held my foot on the brake, put it in drive and mashed the pedal, fuel pressure was between 55 and 60.

Im kinda lost here as to what this could be since i checked the most obvious things.

I will add my water pump is making a bit of noise... can the knock sensor be picking that up and retarding the timing????


Maybe the fuel pump is shitting out during closed loop???(seems the car is fine in open loop)


HELP!!!!

If your fine open loop, and craps out closed loop, then I'd put my money on a sensor. Hook your buddies Tech 2 up again if you can, and watch IAT, TPS, O2, MAF and MAP. Take a snap shot when it acts up and check over very carefully right where it craps out. Something should stand out to you guys

I know you checked the pressure of the cat, but what are the reported values between the #1 O2 compared to the #2 O2 when it does this? Knock sensors in the V-6 are hyper-sensitive so it is very possible that it's picking up false knock. I doubt it though, even knowing how sensitive these actually are.

silly question but if the cat pressures are high... then isnt the cat plugged? would give sluggish symtoms. pull the upstream o2 out and take it for a quick test to see if your powers back (exhaust will excape from the o2sensor hole isntead of being trapped by the cat)

The cat pressure was between 3 and 4 psi... im not sure if thats high

How many miles are on the car?

You say all this stuff started to happen after you bought gas? You know if you buy gas while the truck is unloading it stirs up sediment in the tank and it clogs your fuel filter AND a couple of other things. I don't know about thus car, but lots of cars have a screen by the fuel pump and you could have clogged injectors as well.

105k i didnt see a gas truck that day

Tbh sounds like when my tranny was going out

Sounds like my alero the week befor my Cat clogged completely. Changed out cat all good now.

As dumb as this sounds... it was a bad idler pully

what? how?

Not sure how but i had a screeching noise and thought it was the water pump...so i changed it...tightening the last bolt my hand slipped and i felt the idler below it jiggle, i changed that and everything has been fine since.

i bet it will come back. my car did it when it felt like it. i think it was the tranny.

see if i have the problem with the 6 speed......

My car did the same symptoms when my Tranny was on its last leg. With a reman in it, it is a spunky as ever!

The generals magic strikes again!

Its deff not a trans problem...trust me i smoked 4 th125 with a 3400 in front of them in my 89z24 and 5 trans in my first car 89 olds delta 88 royale brougham. It was deff the knock sensor picking up that bad idler pully the whole time.