Car dies when I push on the gas (Wont go past 5mph!)

[graphikg]

My touring (M50) dies when I accelarate not even past 5 mph. At idle it is a little rough, but I can rev it and the check engine light goes away when I rev; right when I let go of the gas, the check engine light flashes back on. What is it!? But if I put it in drive, I cant even get to 5mph; it dies right when I put my foot on the gas even slightly. I think it might be a vacuum problem? It was perfectly fine. After I replaced my bad alternator, the problem started right when I turned the car on.

[Kershaw]

if it was a vacuum leak, i'd think that keeping it revved would keep it alive.

sounds like a fuel pump or coil?

[e30s50dan]

I would check the battery and make sure you have at least 12V +if not 13V ...sounds like not enough voltage to the ECU

[e46s54dr]

When you installed the alternator, did you mix up the wires by any chance? Also, did you reinstall your maf sensor backwards? There should be an arrow the points in the direction of the flow. Usually new problems are related to your last problem/repair.

[funcrew]

Make sure your air meter connector is fully clicked in place. Had this problem on an M20; no airflow signal to the computer.

[weaksauce]

unhook the maf and see if it idles and revs

[greyis89]

i took the wiring off my icv this morning to see if it had any affect when driving and it drove like you describe. couldn't really hit the gas or anything, it would want to stall. i could just take off and get up 5mph. look into that maybe. im looking for the gremlin giving me too much fuel and sputtery shifting. good luck.

[jrdeamicis]

Grinil,

Unplug the MAF and see if its a metering problem. If it drives ok with the MAF unplugged the MAF is dead.

If it doesn't change, It could be your CPS is dying, (As it gets faster it cant keep up with the sensors)

You can also unplug the O2's to trace the problem being with mixture.

OBD1 correct?

[greyis89]

I've unplugged my maf and got no difference. When I crank it with a friend tapping it it starts good without reving high like it does when he didn't...

[dsobering47]

sounds like a bad vacuum leak.

[greyis89]

I've smoke tested too and found the minor leaks. Administered repairs, stilll pulling hair out!

[graphikg]

It ended up benig a vacuum leak on my 5 series (which is the car that had the problem). It was the hose that goes to the ICV under the intake manifold. Just some tape worked for a temp fix, but need the hose and an air intake boot to feel safer.

[jrdeamicis]

I can send you the one from your e30 :)