Hey guys having some issues with 00 transam.

**00redta88** · 10-05-2011, 06:23 PM

Hey guys new to the forum. Got a 2000 trans am with ls1 manual six speed. 70 k miles on it. I bought the car about a month ago or so. One day the check engine light came and it was hesitating and missing it felt like. the code it threw was for crank position sensor So i replaced that and took care of that code and seemed to act normal after a little test drive. Next day It started same stuff hesitating and stalling this time it threw a code for random misfire and a po420 for catalyst system efficiency below threshold. I got the codes cleared and still hesitated but not as bad as it did when light was on. Well last night ses light came on again threw same po420 code and hesitated and stalled under even light accel and while this was all going on the tach stopped working went to 0 and the car was still was running. shut car off started right back up and tach was working again few mins later repeated it self all over. It hesitates often but only has a bad spell usually under hard acceleration. you guys think it may be the CAM position sensor? Not sure why it throws the po420 while this is going on and for bank 1 and bank 2. Im lost guys any help would be awesome.

**cammed goat** · 10-06-2011, 10:36 AM

Did you buy that car from a private seller or dealership? Without knowing that info, I am tempted to say your pre-cat oxygen sensors are bad since you described issues in both bank 1 and 2. That car could have been neglected by the previous owner and now you will have to make the necessary repairs. Get back to us as soon as you can so we can help you get that bird flying again.

**00redta88** · 10-06-2011, 11:10 AM

I bought the car from private seller. the couple were in their 50's and seemed like honest people. I have numerous oil change records that came with the car. It SEEMED like it was taken care of very very clean. but now i am having these issues. Like i said is stalls and hesitates and sometimes backs fires a little. While this is all going on the tach stops working it just drops to 0. sometimes it only has slight hesitation until you get in the throttle then the issues get worse. It starts up on first crank and idles just fine. I been researching and researching trying to figure out the problem but am stuck! Thanks for any replies guys!

**cammed goat** · 10-06-2011, 11:21 AM

OK. Start off with a good MAF cleaning as I am assuming it hasn't been done. Also, I still say the oxygen sensors need to be replaced. Check the fuel pressure as well as the pump could be weak and in need of replacing. As far as the tach dropping to zero, I am not sure if that can be related to the cam position sensor but I could be wrong. Other members will get in here and help out soon.

***SMWS6TA*** · 10-06-2011, 11:55 AM

CATs might be clogged. That is what I'm thinking.

**cammed goat** · 10-06-2011, 11:58 AM

Originally Posted by SMWS6TA

CATs might be clogged. That is what I'm thinking.

That's what I have been thinking as well...as well as longtubes. SHHHHHHHH!!!!!!

**00redta88** · 10-06-2011, 12:18 PM

would the cats being clogged or bad 02's cause the car to back fire? or cause tach to malfunction it is throwing po420 and po430. which are cat codes.

**00redta88** · 10-06-2011, 12:26 PM

Originally Posted by cammed goat

That's what I have been thinking as well...as well as longtubes. SHHHHHHHH!!!!!!

yeah long tube headers and full exhaust are in the very near future. But just trying to figure out whats going on with this thing if its gonna be simple or a costly repair. If its simple ill order long tubes and exhaust from texas speed next week

**Cutlass** · 10-06-2011, 06:09 PM

The tach problem could be a cam sensor issue. The P0420 and P0430 can really only mean both cats are bad. Might as well change the plugs and wires while doing the header swap as well

**00redta88** · 10-06-2011, 06:47 PM

will do plugs and wires. Bought a cam sensor for it today will install this weekend and see what happens. can cats go bad from back fires into them?

**Deviant LS1** · 10-06-2011, 09:22 PM

The cat's can go bad from multiply misfires. You're dumping raw fuel into them. It clogs and burns them up.

**35th-ANV-SS** · 10-06-2011, 10:31 PM

If you are having misfires, I'd correct that problem along with the cats. If you're running rich and dumping unburnt fuel into the exhaust then new cats are going to be ruined prematurely as well.

Any other codes? Are you sure you're having misfires? Does the SES light ever start blinking?

**00redta88** · 10-07-2011, 09:40 AM

Yes it has blinked on me a few times. but hasnt thrown code for random misfire in awhile. it throws po420 and po430 and when it stalls out and hesitates the tach stops working. I can def hear back firing going on as well.

**TLS_Addict** · 10-07-2011, 12:14 PM

Your front cats are the fuel callers and the rears just check to see if the cat is working properly. If the cat is clogged wouldnt a code for the rear 02s be popping up?

**Cutlass** · 10-07-2011, 12:43 PM

maybe but not necessarily.

**35th-ANV-SS** · 10-07-2011, 12:45 PM

^^^ true. A bad cat doesn't always trigger a SES.

**00redta88** · 10-07-2011, 02:05 PM

Ok now its not throwing cat codes. its throwing po336 crank shaft position sensor A circuit range/peformance. i just put one in two weeks ago. This time tach stops working it dies and runs like crap. Bucking,stalling..etc. but always starts right back up it does idle bad sometimes too. bad sensor?

**35th-ANV-SS** · 10-07-2011, 04:46 PM

Perhaps you have a broken reluctor ring sensor

**Cutlass** · 10-07-2011, 05:57 PM

Besides a possible bad sensor, I suspect crank sensor wiring/connector issues first. This could be your tach problem also.

**00redta88** · 10-08-2011, 02:53 PM

yeah i checked the wiring and plug and it looked good. which i guess doesnt mean anything but insulation looked good as far as being broken or chewed on by pests. but i guess just because it looked ok visually doesnt mean its working properly. Could i check this with a ohm meter or test light?