Hello all I am a new proud owner of a clean 91 244, red with b230f and auto tranny. This cars motor is having some issues that I thought I could sort out fast. Boy was I wrong? After doing much research on the cars issues I started to address what I thought was wrong. The car certainly needed some repairs and the parts I replaced certainly needed it but I'm still having a throttle surge miss at the first part of the acceleration and occasionally a backfire.
Symptoms.
Sometimes when you start the car it will barely idle and then come up normal and pur like a kitten.
If you slowly accelerate it will eventually run up onto the rpm's but if you drive it it has no power.
Occasionally it will backfire and first throttle response it seems like its so lean it's missing. It did drive home when I purchased it with barely enough power on the freeway but would do 70 mph easy and then all the sudden it just barely ran.
What I have done|

Changed plugs
Rotor and cap
Swapped out the ECU from junk yard units with 3 different ones.
Swapped out radio fuse with used one
Swapped out fuel relay with used one
Cleaned MAF
Replaced plug wires with new
New primary in tank fuel pump and filter. The old one was in pieces.
New fuel filter. The old one was nasty!
New engine coolant temp sensor


I have new parts yet to be put on:
New HP fuel pump
New CPS
New o2 sensor
New radio relay
New fuel relay

After all this I'm thinking the cars timing, compression,or catalytic converter might be clogged?
I haven't done a compression test yet but the car runs so well other than the quirk?

Any ideas?

 

No body has any experience or input?

 

Wow will thanks for no help. I guess I'm top mechanic around here even though I haven't fixed the car????
Even so I'm thinking it's my MAF. I have changed the secondary fuel pump, radio suppression relay, 02 sensor, CPS and no lick car still does the same thing.
I did try a flame thrower vw coil with no luck and I had a older MAF that I tried to see if it would work and it mad the car run worse.
I'm guessing that I would buy a MAF hoping that was it! I changed the three ECU that I have and no change.
Any ides?

 

I also unbolted the exhaust before the cat thinking it would be clogged and it didn't help. Any ideas?

 

you are in the wrong section. post in the 240 section. here is for the 6 cyl.

 

I am guessing fuel pump on this problem. It seems to be intermittent, so that would rule out a clogged cat converter. It sounds like you already tried the ignition parts. I think you need to get some instruments to find out if this is a fuel or ignition problem. A pressure gauge tee'd into the fuel rail will tell you if the fuel pressure is dropping. Another way to see what is happening is to connect a multimeter, set to volts DC, to the O2 sensor. When things are optimum the voltage should be around 4.4 volts if my memory is correct. If it stays below 4.4v, then it is running lean.


You can usually get a probe into the O2 connector from under the rubber boot. The other probe will go to a good ground.