Hi, I have an 1988 Trans am with a 350 TPI. I have SLP headers, Flowmaster 3" Exhaust, and high flow cat. My car runs lean at low RPM. I have an adjustable fuel pressure regulator, but no matter how high, or low I adjust the fuel pressure. The car still runs lean at low RPM. I was told to put in a 3 wire heated Oxygen Sensor. They said this will solve my problem. Because of the high flow exhaust system, the factory Oxygen Sensor doesn't heat up right, and gives the computer a false reading. How true is this? Would this solve my problem?

it could help your idle definetly and possibly could be the problem i'm not sure where the 02 bung is located on slps though.

you don't have a vaccumm leak do you? any data from a scanner you could post up of all your live readings?

Whats your base timing connector unhooked set at? If it's increased mildly that has the same seeming effect as having a lean mix.

i just bought a 3 wire conversion harness from tpi-parts.net for my tpi car

but from what i gathered when you run headers the o2 sensor gets false readings because the o2 sensor never gets up to temp due to the higher flow in the header.

ALSO! do you have your air tubes blocked off? If you do the motor will run lean due to the o2 looking for the stream of air being pumped into the manifold.

SLP O2 bung is in the driver's side header, similar to where it is on the stock manifolds and most every other header.

A heated O2 sensor may or may not solve your problem. But it cant hurt.

this board and the Exhaust board for "heated o2 sensor" or "heated oxygen sensor" . This is a pretty common topic. However, its not a direct bolt-in unless you get the adaptor plug Toyota H8r mentioned. Otherwise you'll have to do some cutting and splicing.

If you decide to proceed with installing a three wire heated O2 sensor read my post entitled “Three Wire O2 Senor for a Thirdgen” of about a year ago. I researched this and finally installed one in my 1989 GTA and presented how the project went and the results in that thread. I would recommend using the Bosch three wire O2 sensor and getting a wiring harness from TPI parts.

now i know to look for a Bosch 13077 3 wire o2 sensor but how do you wire it? ive heard you dont want it to stay on all the time or it will burn out

Read the post BC GTA mentioned.

You run its power wire to a switched ignition source, so its only on when the key is turned on.

I will give the heated oxygen sensor a try. Thanks!

3 wire delco number is AFS-74

I'm selling my 3 wire O2 sensor with pig tail connector $100 Brand New in the box. AC Delco #AFS74 Never ended up using it!

I have this same problem, my TPI runs very rough after it warms up and I read similar advice and decided to install the 3 wire heated O2 sensor. Well it did not fix my problem. I check the vacuum lines and they are all good. I tired unplugging the MAF and it ran worse. Without a doubt I can let it sit and cool down and the problem will go away, but the heated O2 did not work for me. I have a 350 TPI with mid tub headers and O2 after the collector. This problem is driving me nuts. Any suggestions or advice would be great.

I got so fed up I went with a MegaSquirt stand alone system. The best thing I ever did to the car. I picked up a lot more power and the car runs amazing!

not to hijack your thread, but how much does a complete megasquirt system cost?
I want to use something programmable in my T/A without having to burn chips.

I know this thread is pretty old, but I was just searching for stuff to try to solve my poor running camaro, and came across this post....

Is this true? I plugged my air tubes after I pulled the smog ****. Could this cause a poor running car?

Yes Bowtieboy42, you'll need to change some parameters in the PROM (the chip inside the ECM) that will make up for the change in the O2 by removing the smog pump. I fixed this and my car idled a hell of a lot better.

I hasd the same issue with my 1986 Vett aftter I put a set of long tube headers I installed a Bosch 13077 3 wire O2 sender in the Bulge of the headers.

2 wires are the same color 1 is power other Ground the 3rd go's to the O2 as normal.

This has fixed all my poor runnig conditions.

Before during start up it would run OK then once it got up to temp as long you foot in it and keeping the Single wire O2 hot worked ok but if you at idel the Single wire 02 whould get to cold and give the ECM a false reads.

The 3 wire fixed all of this.

I ran the power wire to the Fuel pump relay so when the car is runniong the Heated 02 would have power going to it, the other wire to a frame ground.

I actually had my problem fixed. It turned out to be some faulty wiring on the fuel injectors and some of them were turning off. My mechanic fixed it after going over it for a few hours and hooking up the computer. my car was a retro fit so it opens up a lot of room for errors liek this. i did however install the 3 wire O2 sensor and feel better now that i have a heated sensor. good luck to all.