Yeah, there are a lot of people giving out crappy, nieve advice on this site. Get advice from someone who knows your model.

 

I also have a 98 gt with the pi swap, intake and heads, i have been running on the factory tune since febuary, the only thing i notice is that i get what sounds like really lite pinging when i tip in the throttle going up hill in 5th gear, i always run premium, i have swapped out the thermostat for a 180, and also put in a egr restrictor gasket, but still it does it, no check engine light, no other problems.

 

I had the same problem with mine, around 1.5krpm when i got on it with no tune. Once I got a tune into the correct AFR it went away. My issue was it went very lean under (or close to) WOT under 2krpm (like 16 or so then dropped to 15.5 ish from there to redline). Once I got it between 12.5-13 ish it ran like a champ and i was also able to add a few more degrees of timing to gain extra hp.

My advise is to get a tuner & wideband or a dyno tune. and avoid low rpm WOT in the mean time.

Do you also have a sound on cold start ups, like a quick pinging noise right from the start?

 

That's going to happen everywhere. There's a few people who really know. This forum is full of lots of misinformation though. -eventually- the right answer will make itself apparent.

If you have any more questions about tuning, just shoot them my way. I'll do my best to field them given my experience. Running my car at 10psi with no problems on a tune I've created myself so that'll probably account for something.

 

No i dont have any issues on cold start, it runs really good cold, i think it may be the timing more than the fuel, as far as the pinging is concerned, the car really runs strong at wot at any speed, its only low rpm load that seems not rite, and the noise is so lite you have to roll up the windows and really listen for it, i read that the factory cam gears give - or + 4 degrees of timing depending on how they were setup, i also just started having a problem with my fuel pump, car wont start, no fuel pressure, so i also am thinking that the problem could be fuel pressure or volume, i still have some bugs to work out, just gotta get the cash flow to fix them, that damn fuel pump is exspensive, OH STILL NEED TO KNOW WHAT PLUGS TO RUN????