rough idle/misfire

[busyb187]

Hey everyone OK so I have a 97 gst stick shift. It has a bad rough idle. Its idleling at about 950rpm but feel very rough. It kinda feels like its misfiring. It slightly fluctuates between 900 and 950rpm... I have replaced isle air control, tps, ecu, spark plugs, wires. I did a compression test and cylinder 2 and 4 read 145psi and cylinder 1 and 3 read 150psi. I did a boost leak test and heard hissing noise from plastic whose that connects bov to inter cooler. Replaced and still the same. Don't know what else to check or what to do. Runs great just problem at idle. Can't seem to find any leaks and car is pretty much stock except for bov n intake. Also has fairly new timing belt. Checked timig with timing lite and the mark on harmonit balanced is in line with the "T" mark on engine. Please anything helps at this point. I don't wanna have to get rid of it. Thanks in advance!!! Oh and have no trouble codes.

 

[undefined0000]

O2 Sensor?

 

[busyb187]

You think a bad o2 sensor would cause these issues? Shouldn't a cel come up with o2?

 

[undefined0000]

I would that that it would, but with no afr reading, its hard to tell. I've seen an eclipse, the same year with a bad O2 sensor, and it idles and just straight misses every now and then. But he had a cel.

 

[busyb187]

Yeah that's what's killing me, the no cel...

 

[Build01Laser90]

Test the Coil pack?

 

[busyb187]

OK I replaced coil pack because one had a small crack. Problem still continues... I'm going crazy here... I love the car but I want it to be in good condition...

 

[nickk90]

A Denso o2 sensor is like 40 bucks.

 

[Rsawd95dsm]

A Denso o2 sensor is like 40 bucks.

Where did you find that deal? I payed 65ish for my o2

 

[Arcangel2501]

check your timing on ther car make sure both cams are in timing mine was doing it and i check everthing iac tps o2 sensor and everthing then i seen it was 2 teeth off on the cam and put it back into timing and it ran fine