Weird issue under power

[///Maybach]

I'm hoping someone can shed some light or has had a similar problem with their e30...

The car is a huge work in progress, it is a 1991 325iX with 100K miles.


Now for the issue.. When driving up a hill, the engine seems to cut in and out. There also seems to be a lot of hesitation when having the pedal down and it's going through the higher RPM's. This problem seems to be worsened when the ac or even just the fan is running. It feels very similar to running out of gas. I have attempted this in 1,2,3 and Drive, it seems to be consistent in all gears but 100% not transmission related.

Possible causes -- There was a crack in the intake boot but I replaced that. Idle was strange and found it to be a loose fuel line off the fuel pump. Intake filter looks a little old/dirty and needs to be replaced, there is a crack in the flex tube on the exhaust just before the O2 sensor. There is also a possibility of some old/bad gas.. However it idles perfect and doesn't have a bad gas smell..

Any help or pointers are greatly appreciated!

[ethrty]

these questions are always hard to diagnose over the internet, there are a number of possible causes.
dirty air filter will not cause this issue.
crack in exhaust flex may cause higher than expected O2 reading, however generally exhaust gas would be escaing here rather than being let in. hey you are gunna have to fix this urgently anyways, would be a good place to start.

my money is on the dizzy cap, and or rotor, mainly due to the milage of the vehicle. 2 minute check with an 8mm socket. look for heavily worn points, and oxidisation on the rotor with wear back to the plastic.

if that checks out, check resistance of crank position sensor, should be about 540ohms.

other things like poor coil strength, excessive resistance of spark leads, bad fuel pressure regulator, etc can all cause similar issues, which wouldnt usually expect at that milage, however these cars are 30 years old now

[15Michaeljoseph]

I think you should take a look at your spark plugs, in addition to everything above. Are they old? Are they the correct kind (copper core)?

[BobombETA]

^ this and

Old/bad gas makes it sound like it's been sitting, which can really gum things up in your fuel system.... I'd put new gas in it and work your way forward, replace your fuel filter and pull and clean your injectors.