NOrmal Idle, but it fast idles when cruising

[bronxbombr]

dude, its either the iac or tps thats it.........................

[mko]

Dude i dont have an IAC.

[mko]

OK, what we did today:

Swapped galants fuel pump with Evo one.
Blocked off the EGR.
Put injector cleaner in tank.
Readjusted all TB sensors and fuel pressure.
Bought a feeler gauge and the funny thing is that I set the gap of spark plugs to 0.3 with one of these coin gauges, well they suck. The feeler gauge says I had 0.8mm of gap...I was like WOW.....so i set it to 0.3mm for real this time
Bought new O2 sensor, havent installed it yet cuz I didnt have the socket.

Tomarrow I will :

Install the O2 sensor /hoping its the problem/
Install different distributor
and see if I can find another MPI relay /if someone has a spare one, gimme a holla/ 94 MPI relay is a single piece with 8 pins.

[mko]

So nothing, New O2 sensor and still nothing. Im thinking the worst - bad HG

Still havent got around changing the MPI relay, Distributor or ECU.

And on top of all this, my windshield cracked.

Im tired of this car

One more thing. can the lower thermostat cause this, I mean switching back and forth the low and mid trims. I still got the 170 deg thermostat in

[Galanttuner10]

i think if it were the bad head gasketunder boost would be shitty too.. it goes rich so maybe a leak behind the MAS idk its weird chris wish i could help you more

[Ivory8g]

if it were a head gasket there would be a hell of a lot more issues than idle. did you reset the ecu after the o2 sensor? that is vital. compression test homie. report back.

[mko]

Dont have a compression test tool.

anyway, I was outside and retarded timing a bit and now it does it less, but still does it. IDK

[mko]

Well did a compression test - 200 across the board. Not bad when having 230k on the clock.

So its either fuel issue or more likely a spark issue - dizzy is going bad

[mko]

So, I think Ive found what is causing this. Ill post later when i fix it.

[seth98esT]

Coolant temp switch????

[mko]

ok, a little update.

So, I zeroed out the SAFC and reset the ECU. It idles like it used to before I installed the SAFC, around 18-19, but I has no hiccup anymore. I drove around and it behaves ok. IDK if its the wet/humid weather, but it acts like i dont have a MAFT - when I shift AFRs go straight down to 11.0 for a second and then recover back to normal. It didnt do that in the summer tho. Im confused. I may switch to draw thru setup instead of blow thru sometime this winter.

[mko]

So far, i Havent messed with fuel system only. Upgrades i have done to it:

Aeromotive FPR, Evo9 pump /not rewired/, braided lines,summit racing high flow fuel filter, earl's 6an fittings, fuel rail fittings.

I replaced the main ground wire today, and still does it.

i was told it could be clogged cat. I have 3'' high flow magnaflow cat and 3'' cat back. still have the silencer.

It really weird. i dont hear any popping or misfire. its very quiet and muffled like its a post MAS leak. It usually does it at 10% throttle and when i keep my foot steady. If I accelerate its fine. Its random, not it pattern. It happens more often after its been in boost. Idle is at 22hg/inch. I removed the charge pipe before the GM MAS and still does it. I was having problem with one of the TB nipples, it was clogged, but I fixed it. The only other thing i can think of is bad TB.

Could it be some kind of pre-ignition?

[mko]

So, I did a few things today. I was trying to eliminate things one by one on top of what Ive done so far.

Switched back to my OEM fuel filter /brand new/ and filter to rail line, installed different TB and just in case I switched to 510cc. Well, the thrill of 510cc acceleration felt nice, but my hiccup problem still persist, and its driving me crazy.

Things Im doubting that might be the problem:

Aeromotive FPR, distributor and HG.

[mko]

so, I put new coolant temp sensor and switched back to my stock fpr, and guess what, its still doing the hiccup. So most likely i have an ignition problem. The distributor is probably going.

[mko]

SO SO SO, I got it fixed. OMG what a relief.

well the MAFT needs a RPM signal so u can tune with the knobs for low, mid and wot, but I dont use it since I have the SAFC do the fine tuning

Anyway, I had the wire tapped in the distributor for RPM signal, and soldered there. i was playing with it today and wiggled the 2-pin plug and it kind of did the hiccup, so I was like hmm and pulled that wire off and tada. so the MAFT was stealin the signal form the ECU to the distributor - making it weak enough to trip the power transistor shut meaning that the level of the incoming signal was so low that the power transistor wasnt able to open at times....doing the hiccup. Thats why it was quiet, and not like a misfire sound /pop/