I have an 89 240sx sohc that I bought recently, just finished replacement of T-chain. The car has a problem that I suspect was unrelated to T-chain. If you go 100% throttle from idle the engine will stumble and studder, staying at around 1k will do it forever. If you gradually come off of idle the engine will rev to red line. When driving stomping the throttle gives an "accelerator pump gone bad" type symptom then seems to accel better at part throttle than full. Also pops through exhaust and has intermittant rough idle. Timing is set right 15 btdc, TPS is adjusted properly and appears to smoothly increase to correct voltage at 100%, Maf increases voltage with tps %, Checked CTS seems right, no EGR issues, cleaned throttle plate, new cap/rotor/wires/plugs, no dead cylinders, has good compression. I tend to suspect the MAF because of previous experience but dont have lab scope available to test correctly. I also cant remember how to pull codes on the old computers without a MIL on the dash, any direction would be appreciated, I've spent as much time chasing this as it took to do the T-chain! Thanks

Hate to ask but did you have this problem before you replaced the timing chain? You may have gotten the cam timing off. If the dist is turned fully to the rt.or lt. to get it timed than you may have the cam or dist. timing off. To check airflow v.at idle should be 1-3 v. on b/w wire 1v. idle and encrease to 3v. White wire key on batt. voltage. Key off airflow disconnected black wire to grd. meter on ohms 0 ohms.

did you ever fixed this problem? Seems like my 89 that I just bought has this problem also... Although I havn't picked up the car yet, I'm suspecting it might be the fuel filter, fuel pump, injectors, or fuel pressure regulator/vacuum leak