URGENT HELP!! 92 325is breaking-up and loosing power during acceleration

[R_F_L]

Hey guys, this is my first post on the forum. I've posted similar posts on other forums, I got some helpful tips but I need expert advice. About 1 week ago, I purchased a 1992 325is with 152k mls. The car was runnig very clean and smooth. So, I decided to tune the car up, I changed the oil (fully synthetic), oil filter, air filter and spark plugs. I ended-up changing the spark plugs 3 times because the first two sets were platinums and they almost killed my engine. I bought the stock plugs and the car ran better.

Here's the problem, after the car warms-up while driving, it starts to rattle and jerk when accelerating in 1st and 2nd gear. I cannot keep constant RPM and it's really slowing the car down. Somebody told me to check the codes on the OBD but I couldn't get anything with the steps on the manual. Some other person told me to check the intake hoses and boot for rips, I did and found two BIG rips on both ends of the boot. Now, I ducttaped both ends tightly. I thought that would solve the problem but it did the same thing when I took it for another spin.

I also looked-up jerking and rattling in the manual and it said some thing about uneven octane levels and premature detonations. I think that could a contributing factor since I do hear these loud sporadic explosions accompanied with the rattling. I really need to get this fixed because this is my only ride to school. ANY ADVICE??!!

Thanks you guys in advance,

RFL

[Jeron]

I would replace the damaged intake tubes because it sound like air is leaking into the intake after the MAF. Check for damaged vacuum hoses. Replace your fuel filter.

Make sure you properly torqued your plugs and replaced the ground wires on the coils (2 ground wires I think).

[many944s]

I would check the DME as well to see if it has a perfomance chip. I have a Bavarian Autosports chip in mine, and have all sorts of idle fluctuations when running regular unleaded pump gas. I have to use mid to high grade fuel, or use a "gulp" octane booster. I usually try to alternate tanks of gas between high grade and low grade with octane boost. Since I have done that, I have no problems with idle swings. And.... Just as a test to this theory, about 2 weeks ago, I filled up with regular unleaded.... Idle fluctuation returned... added octane booster.... fluctuation dissappeared

Good luck,
-Nick

[R_F_L]

Hey guys, thanks for the replies. I kept trying to get the fault codes and the OBD finally responded. All I got 1444,1444,1444,1444,1444...... for almost 5 minutes till I shut it off. This means that there are no reported problems and just made it a bigger mystery.

Jeron, can a dirty fuel filter cause something like this? The sparkplug packs had something like twist 1/2in this way and blahblahblah...Is that torquing the plugs? Because I usually twist them till tight. What now?

[Jeron]

A clogged fuel filter, bad pressure regulator or bad fuel pump can cause bogging while accelerating. Unless you know when the fuel filter was changed I would replace it. You should be on your third filter anyway.

The holes in the intake boot that you duct taped are a very good possibility. I would replace the boots.

Many944s octane suggestion was a good one too if it has a performance chip, especially if it is a 93 octane one.

You should be able to hear loose spark plugs a a thumping or putt-putting, exhaust leak. You really need a torque wrench, even a cheap one, to make sure they are torqued properly. The last plugs I torqued on my M3 had a stiff resistance before they reached proper torque. If I had been doing the by hand I would have left them half a turn loose. However, I doubt plug torque would cause a strong bogging.

Did you check the ground wires that go to the top of two of the coil packs/plugs.

I would pull off the whole intake boot and check for leaks and obstructions.