97 Tracker - Poor Idle, Hesitation

[Mike8500]

Hello and welcome!
The EGR surly can case pinging. when dead.
no scan tool to see what's Up DOc.?
use the full scan, of all PIDS, using a real scan tool,not just a code reader.
hot idle engine:
ECT reads live at 180F holding? 82C. or more if running hotter STAT.
in closed loop at idle? stated in scans it does.
02 sensor swings nice,?
LTFT near minus 5% not -40 or +40%?
#4 exhaust header tube not cracked, (under shield)
121's are real if it repeats.
when you manually cycle the EGR main, the engine must drop; from 800 normal hot RPM to 400 or stall. did it, if yes, the egr paths are ok. (this car is mono port, just 1 path)
that maf test implies its too lean, normal.
so it bogging below 1/2 throttle (says lean)
low fuel pressure,? FPR bad,?
put back maf, and remove o2 sensor, (unplug it) change symptoms. if yes, look for exh. leak near 02.
are you subject to smog testing, MOT or what ever? it is called there.?

cheers and happy new year




.

I do have a bluetooth OBDII transmitter and Scan XL to do datalogging.

Hot idle it reads about 92*C.

I'll double check but I'm pretty sure it was in closed loop at idle.

O2 sensor is swinging properly, except when the vehicle almost stalls it drops quite low for a split second.

LTFT is normal.

I will check exhaust manifold for cracks but didn't see or hear anything after changing the o2 sensor and checking for leaks.

The 121 code showed up once and has not returned. It popped up after i let it sit there and idle rough for about 10 minutes.

When I pushed on the EGR diaphragm the engine stalled.

When the MAF is removed, it runs smooth with a slightly higher idle (1200rpm) Could this not also indicate it running too rich?

I'll try unplugging the o2 sensor and see what happens.

There is no smog testing where I live.

Someone mentioned the cat could be plugged??

Thanks for the help so far.

-Mike[/color]