Hesitation/Misfire Problem? Help

[OOMPH!]

Just bought a 1989 325is. Trying to diagnose a hesitation problem and need some suggestions/advice. If you accelerate slow the car responds fine, however if you get on the gas hard the car will hesitate. Instead of a gradual increase of power it hesitates and feels very choppy like it's skipping. Already swapped an AFM so ruled that out. What else could it be?

Thanks for the help in advance!

[e30s52]

Possible a bad ground.

[mrsleeve]

FPR, Fuel Pressure (aka pump), TPS, CPS, plugs, how bout some more to work with

[structured]

Check in the M20 section. This has been discussed alot.

I had a misfire which ended up being the harmonic balancer (vibration damper): http://www.r3vlimited.com/board/showthread.php?t=147102

[KillaCam]

O2 sensor I had this prob. is it like giving and taking

[E30SPDFRK]

Could be a weak coil too

[mrsleeve]

Could be a weak coil too

yes it could be, but since its fine under light acell, and light loads, I am going to lean to a fuel demand/delivery issues 1st.

[barry]

Its a fuel problem, filter,hoses, injectors, vacuum, throttle body, idle adjustment, Fuel pressure, pump, Other- rotor, distributor cap, plugs, plug wires arcing.
Good luck
Barry

[OOMPH!]

Distributor cap and rotor has been changed but the problem is still there. The plugs look good and fairly new. The O2 sensor looks on the new side. If it was a fuel related problem wouldn't it do it during all acceleration? This problem only occurs when you step on the gas hard. The car idles very smooth too. I still have to check all the other things you guys mentioned! Thanks for all the suggestions so far!

[xwill112x]

nope. WOT will make fuel issue's WAY more apparent. i would check the cap and rotor if it were me tho.

[bmwE30/541]

plugs wires coils..

[mrsleeve]

. If it was a fuel related problem wouldn't it do it during all acceleration? This problem only occurs when you step on the gas hard. The car idles very smooth too. I still have to check all the other things you guys mentioned! Thanks for all the suggestions so far!

Nope the fuel demand at heavy and WOT is way more than light acell. SO it will show up there 1st

[Huff]

Check your main engine ground. Make sure the contact point isn't rusted (if it's doing under hard decelation too). Otherwise, it could be your intank fuel pump (the main one).

[OOMPH!]

FPR, Fuel Pressure (aka pump), TPS, CPS, plugs, how bout some more to work with

I forgot about this thread.....You were right. The previous owner put the wrong plugs in and the wires were bad. ;)