I have a bone stock '03 3.8 controlled by a '99 computer. I have changed all sensors except the second o2 sensor in the cat (I will do that shortly). The motor seems to warm up quickly and not cool down all that fast when cruising or running the ac to turn the fans on (I have a new heavy duty rad). It also has a very very slight part throttle lean stumble when fully warm, it seems to heat up quickly which leads me to believe it's running lean, other than that the car runs perfectly.

Question 1: How do I discern a lean condition cause by a manifold leak or clogged injectors from a improperly programmed eprom?

Question 2: I know I can buy a switch to change fan on and off temps, I'm told the computer controls when the coolant fan turns on and off (about 212 and 202). Is it possible to change these temps with programming?

Question 3: Will a stock engine run fine (no bogs) at the stock setting (is that 14.7AF)?

 

Visually inspect the manifold, carbon traces almost always show up/

Clogged injector will show as lean with a bizzare 02 fluctuation on the bank affected(u will see it) Will show up on datalogger and also a wideband

At 14.7 you should be able to drive around normally without issues.

Medium/heavy throttle will feel lazy unless your also adding the AE and WOT PE

later
Jeremy

 

You lost me, carbon traces? Are you talking about cracks in the manifold (the plastic portion)?

How do I tell if the injectors are clogged other than a lean AF ratio?

Can a dirty injector always be seen with a visual inspection?

If they are clogged what is the best method of cleaning them THROUGHLY?

I haven't seen many posts for MAF systems:

What analyzer do you recomend for an OBDII?

What book would you recomend on OBDII

Is the stock computer trying to attain an 14.7AF?