New bird problems

**Firebirdformula99** · 10-12-2011, 08:58 PM

So i just bought a 98 trans am the problem im having is it bucks around 2 to 3k rpms and has trouble starting up and has a rough idle i took it to autozone to get the codes read it said low voltage bank 1 and 2 on the o2 sensors and ive noticed either the thermostat is stuck open or theve taken it out would the water temp sensor be telling the o2 sensors something and causing that?? im going to be putting in lts and changing the plugs and wires and motor mounts with polys this weekend so im hoping that will take care of the surging also could it be a dirty egr valve?

**tatertot91** · 10-12-2011, 09:33 PM

I'd start with a basic tune up. You mentioned plugs and wires, i'd also do the fuel filter and get some crc maf cleaner from your auto parts store and clean the maf sensor.
Also look into replacing your o2 sensors, mainly the ones before the cats. Those are the important ones.
Highly doubt its the EGR valve, wouldn't cause your symptoms

**cammed goat** · 10-13-2011, 12:44 PM

Whenever you have a "lazy" O2 sensor, that means time to replace.

**Firebirdformula99** · 10-13-2011, 06:19 PM

ok ill change them when i do the headers this weekend also i changed my thermostat thinking the old one was bad it still acts strange if it sits and idles it wont get over 210 but when i take off and drive its around the 180 mark is that normal? my formula stayed at a steady 210 could it be a bad guage on the dash or somthing like that? i also took off my egr valve and cleaned it the check engine light went off till i floored it which was strange i thought to

**cammed goat** · 10-13-2011, 06:26 PM

I could be wrong, but I think 210 is normal for a V8. Especially with an OEM thermostat as that is set to open at I believe 190 degrees.

**Firebirdformula99** · 10-13-2011, 06:30 PM

Thats what I thought to It just kinda made me wonder

**pajeff02** · 10-14-2011, 04:18 AM

A messed up MAF is also a likely culprit. Our car's stock MAF had been hacked up and it had a stumble right around 1,800 - 2,000 rpm when we bought it. As suggested by Tater, plugs and wires are probably a good idea. The '98 is the only model year with a working temp gauge, so it can generally be trusted. If the thermostat is stuck open, it is probably keeping the PCM from switching over to closed loop as that is dependent upon the coolant temp. In open loop, when the engine is cold, the PCM does not accept input from the O2 senders to adjust fueling -- rather it is simply running off the tables.

**rschap1** · 10-14-2011, 10:01 AM

I have been fighting a "surge" that sounds sorta like what you are describing as bucking.
Mine is a 3800 Grand Prix but looking like a MAF sensor. I am replacing that this evening.