[96-5oh]

To start I'm a new member and this is my first post, I've gotten a ton of great info going through the threads on this site but could use a little more. Any and all help would be appreciated.

So I recently purchased this 1996 mustang it was originally a 3.8l 5-speed it now has a 1995 5.0 motor with the U4P0 ECU but still has the manual transmission. Last few weeks I've been trying to work out the few problems I've had with it the first being that it hesitates while accelerating, changed the junk e3 plugs over to motocraft coppers gapped at .54 seems to have cleared up a bit, and the most annoying is the rpm surge when I engage the clutch. When I first noticed this problem I went through all the vacuum lines and found that the vacuum line running to the pcv was not hooked to the pcv, hooked it up hoped for the best but no change. Replaced the air filter, cleaned the maf, throttle body,iac, and checked the tps which was at .97. The CEL is on and I tried a couple different scanners but couldn't get a reading with the obdII hook up and obdI motor and ECU. Today I finaly found a thread explaining how to check using the EEC Test under the hood this is what I got:

KOEO

637 Transmission fluid temperature sensor
654 MLP Sensor not in park
563 High Speed fan circuit failure
621 Shift Solenoid 1 circuit failure
622 Shift Solenoid 2 circuit failure
652 Modulated lock up torque converter clutch failure
624 EPC Solenoid or driver circuit failure

332 Insufficient EGR flow
624 EPC
637 TOT Sensor circuit above max volts
639 Insufficient input from transmission speed sensor
667 Transmission Manual lever position Sensor circuit short
668 Transmission range circuit volt above max

will do KOER and cylinder test tomorrow

So my biggest concern is the ECU, does it have to be changed? and any help with how to solve any of these codes would be a huge help. Thanks

[96-5oh]

Udate: For all of you readers


So I finally was able to get my hands on a T4M0 for the mustang swapped it out the other day and took it for a test drive, leaps and bounds better but still not quite where she should be still has slight idle issues when first warming up but then it evens out in 20-30 secs and also slight surging when the clutch is engage but again not nearly as bad as it was. Again I ran the KOEO and KOER:

KOEO
563 - High speed fan circuit failure
111 - Passed

KOER
314 - AIR inoperative, left or front HO2S
311 - AIR system not working, single right or rear HO2S
332 - Insufficent EGR flow
411 - Cannot control RPM during KOER low RPM check

Also passed compression test on all cylinders twice in a row.

Now from what I've read 314, 311, and 332 can all be tied together with some sort of vacuum leak keeping in mind that both my Smog and A/C pump have been removed. 411 Could be that my idle is set to high? And I would think that the 563 has something to do with the A/C as well. Like I said much better than the 15 codes I was getting before the swap. Any feedback would be appreciated

[2Manystangs]

I would have just sold the 96 and bought a 95 gt

[96-5oh]

Well that was my first thought and if this car wouldn't have been in such great condition body and rust wise I would have.

[96-5oh]

Update:

Pulled off my passenger fender today to check on the vacuum lines running to the egr, found that the vacuum line running from the charcoal cannister had deteriorated so I replaced it also replaced a couple of caps and the fuel filter put everything back together was looking around a little more to make sure that I had everything put back in place and noticed that the green line running to the egr had broken off followed it all the way back towards the air intake and also found that the peach colored line that runs to the smog pump (I think) had been cut off and glued inside? messing around with that connection relised that the bottom of that piece had broken off so i cap that as well. Started it up and took it for a drive NO IDLE ISSUE!!! Will replace all of those vacuum lines tomorrow, reset the base idle, check the timing and report back. Thanks for reading

[96-5oh]

Update:

Replaced almost every vacuum line at this point, reset idle and computer, NO CODES!!! Cfars running great might have set the idle to low does stall out at stop lights sometimes ill fix that in the morning. Alternator is whining as the rpm increases im going to pick up a new bearing tomorrow and see if thats the problem not having any issue with the charge. Also looking for a new set of headers was going to just replace the gasket as there is a leak on both sides but there seems to be a pin hole in one.