Trans Am

So i began with MAC Headers and a catalytic y pipe. Car ran great no problems. I get my long tubes, cats, and Y pipe installed and the car doesn't run good. The guy installing them broke my coolant temp sender but replaced it. SES light came on, it was my O2 Sensor and that was replaced. The car can now idle and rev fine. But still doesn't run good under 2K RPM or Over 4K RPM. While i was at home i decided to change the spark plugs and only one looked different from the others and that was the one that they bad coil was connected to. So I get my car checked with a Tech II and the number 4 cylinder coil wasn't always firing so i had them change it out for a new one. The car is still running the same way, never had any SES lights at all. Under 2K RPM the car feels like it hops and or misses sometimes especially when i give it some gas. But when im flooring it, it'll hop before it gets to 4K RPM and then over that it starts to backfire. I can't seem to figure out whats going on. Should i get it on a wideband and dyno and check AFR? When i got dynoed with my macs and cat y pipe my AFR was 13.0 to 12.7. So what could be the problem? PLEASE HELP

JRcamaroZ28

iTrader: (41)

Might just want to check and see if all the plug wires are on tight. If you have A_tap and MAF-T yoou may want to do some logs and see where everything is now as in the LTFT's and o2's.

JR

WS6FirebirdTA00

iTrader: (33)

i know this might sound dumb but i have to ask, are you running the off road pipes? and if so do you have o2 sims? like i said it might be a dumb question but i have seem that happen before... <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

Trans Am

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by JRcamaroZ28:
<strong> Might just want to check and see if all the plug wires are on tight. If you have A_tap and MAF-T yoou may want to do some logs and see where everything is now as in the LTFT's and o2's.

JR </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Yeah the guy who put my new coil on made sure all the wires were on tight. I'm waiting til thursday to go back so they can diagnose my car again.

Trans Am

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by budchevy8:
<strong> i know this might sound dumb but i have to ask, are you running the off road pipes? and if so do you have o2 sims? like i said it might be a dumb question but i have seem that happen before... <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">No i have 3" carsound cats. Yes i do have O2 simms on the rear sensors.

01Z0H6

iTrader: (63)

TransAm. What did you do with your Mac's??

Trans Am

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by PewterY2KZ28:
<strong> TransAm. What did you do with your Mac's?? </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Still have them, just waiting for them to finish putting the off road pipes on it and fix a hole in the driver side header.

SSTYCOON

iTrader: (2)

it can't be too serious if you don't have a SES, i would replace the plug wires. long tube headers has nothing to do with your motor missing.

Trans Am

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by SSRIDAZ:
<strong> it can't be too serious if you don't have a SES, i would replace the plug wires. long tube headers has nothing to do with your motor missing. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Yeah thats what i was thinking too. I'm going to replace them. hell im at 53k miles anyways its worth it.