Low RPM Studdering

[Jacksontheogre]

I just purchased a 1987 325e for $650. Right off the bat the car jerks ans stutters in every gear at low RPM it almost feels like its a fuel cut. At higher RPM's there is no issues. I look it to my local euro shop to have them go over it. I had them do a smoke test and adjust the valves do see if this help it, and I did't. Yesterday I changed the oil, filter and put some Restore in with the oil as well as added some fuel treatment to the fuel tank. Also I replaced the spark plugs and check the injectors. Again low rpm or if the engine is cold....jerk and stutter but at High RPM fine. Any thoughts?

[e30trooper]

check your plugs?

[Jacksontheogre]

check your plugs?

Just checked them again, them seem fine no buildup or anything

[wcipolli]

I have the same issue! I replaced coil, wires, plugs, dist cap, rotor, injectors, timing belt, water pump, crank position sensor, coolant temp sensor, fuel pump, fuel filter, most air hoses, intake boot, valve cover gasket and valve adjustments, o2 sensor, cleaned afm and icv.
Three oddities I've noticed. If I unplug the AFM the car runs the same as it does without it besides the CEL being on. A local mechanic says he thinks that may be the issue as these e30s use an "average" if its not getting a correct signal from the AFM. Is there a better way to test this than buying a new/used one and swapping? Rarely, if I'm at a stop light, the CEL will go on until I hit the gas which immediately knocks it off. After this happened I decided to do the stomp test, which worked once in about a hundred tries. I did it every time I got to my destination until it worked. Code 1222 Lambda control 1 came out.
Given all of this information where should I start? Do all of these puzzle pieces come together pointing towards one thing? Analytically I'm thinking the tps might be the issue?

[mr.vang]

replace the fuel filter to see if it help

[wcipolli]

I missed that. Fuel filter is new as well!

[paperplane94]

check fuel pressure, possible bad FPR. Also check the resistance of the temp sensors since the problem is temp related. Adjust the TPS.

[wcipolli]

Any link to a TPS adjustment DIY?

[BergerNJ]

before replacing parts diagnosis is needed first....

[jlevie]

I have the same issue! I replaced coil, wires, plugs, dist cap, rotor, injectors, timing belt, water pump, crank position sensor, coolant temp sensor, fuel pump, fuel filter, most air hoses, intake boot, valve cover gasket and valve adjustments, o2 sensor, cleaned afm and icv.
Three oddities I've noticed. If I unplug the AFM the car runs the same as it does without it besides the CEL being on. A local mechanic says he thinks that may be the issue as these e30s use an "average" if its not getting a correct signal from the AFM. Is there a better way to test this than buying a new/used one and swapping? Rarely, if I'm at a stop light, the CEL will go on until I hit the gas which immediately knocks it off. After this happened I decided to do the stomp test, which worked once in about a hundred tries. I did it every time I got to my destination until it worked. Code 1222 Lambda control 1 came out.
Given all of this information where should I start? Do all of these puzzle pieces come together pointing towards one thing? Analytically I'm thinking the tps might be the issue?

In this case the Lambda fault code and the behavior of the CEL strongly suggests intake leaks and/or aged O2 sensor. The O2 sensor is a scheduled maintenance item with a replacement interval of 100k. Unless you have proof that the sensor has less than 100k on it, replace it. Then have a shop run a smoke test on the intake and fix the leaks it turns up.

[wcipolli]

I replaced the o2 sensor 6 months ago. Is anyone aware of a shop in CT with a smoke machine? Any home made DIY?

[paperplane94]

Any link to a TPS adjustment DIY?

yes, the haynes M20




Basically, 2 & 18 must have full continuity while the throttle is at idle position.