wierd idle help!

ok i have an 88 gmc jimmy s15 4.3 4x4. i have an airaid throttle body spacer installed and i cut the air filter top around only where the inner K&N air filter is so its exposed. I also raised the advance for more power(might be the problem)
now my problem is, is that:
#1 when I start the truck it idles extremly rough. therefore i gas it and it returns to a smooth idle. that problem went on for about 2 weeks.
#2 on my way to the shore i was trailering me jet-ski and my motor began making an extremly loud noise through the exhaust. the noise didnt sound bad like a knock, but it it very loud. so i pulled over and replaced my intake cover, figuring there was too much air. (i have an extra for when it rains) i bearly made it to the place and back

on the high way i kept a consitant of 2500 rpm and about 55 mph +-
it cant really raise higher that 4,500 rpm because it seems to resist alot.
when i had the cut intake top i could redline about 6 something(passed the stock tach) maybe i redlined too hard...im not that experienced and i would appreciate any feed back thanks

get refund for spacer and put the intake / airfilter bac the way it was before the problem started.:2cents:

so think the spacer is giving me problems along with the air lid? would the advance have anything to do with it? l'll replace the intake and take off the spacer and get back.. thanks

so think the spacer is giving me problems along with the air lid? would the advance have anything to do with it? l'll replace the intake and take off the spacer and get back.. thanks
also try backing off the timing a little untill it makes a difference, sometimes too much advance can do permanent harm.
is there pinging/knocking when you tried to rev higher than you stated? or any backfire?? these would be huge tells that there is too much advance.
does an 88 have the electronics to detect knock/ping? if so, maybe that is why it won't let you get higher rev's.
good luck, hope you get it back.

i just got back from the shop, apparently the fan clutch needed to be changed. hopefully it will help, also when it gets running again ill lower the advance.

i just got back from the shop, apparently the fan clutch needed to be changed. hopefully it will help, also when it gets running again ill lower the advance. if it ain't too late, i removed my 01 fan clutch and fan and installed an electric dual set up with a thermostatic switch, but you really need to want to do this cause it ain't a ten minute install like they tell ya. just a thought, give you about 8 hp back, but it will cost 150-200 bucks usd for you to do it yourself. if you have a shop do it, its probably 2-3 hrs labor. minimum.
just a suggestion.
:2cents::2cents::2cents:

its ok when i got to the shop they replaced the fan cluth ...its too late for an electric one owell. but i think the motor still sounds loud i started it up on friday before they closed while it was on the lift. i didnt lower the advance niether did i take out the spacer...also my tranny was slipping and i was in for a tune up that should be tied in wit anything???...any suggestions???

its ok when i got to the shop they replaced the fan cluth ...its too late for an electric one owell. but i think the motor still sounds loud i started it up on friday before they closed while it was on the lift. i didnt lower the advance niether did i take out the spacer...also my tranny was slipping and i was in for a tune up that should be tied in wit anything???...any suggestions???
I'm just a shade tree mechanic, so this is just my 2 cents, but i would seriously put timing back to where it was before and remove spacer, just to eliminate those as possible culprits in the system. the tranny slipping, is an odd symptom and don't know how it fits in the original problem. is your truck all original? any other performance upgrades? advancing the timing is usually a trick used after a performance cam is installed, or if you are using really high octane fuel and the engine can handle the timing change. my last truck up untill the 01 i have now was a 75 gmc 350/350 4X4 that the only thing electronic was the radio!! is the shop you go to using seasoned mechanics that you know, or are highly recommended, or are you just an atm to them? changing the fan/clutch should not make the tranny slip.
good luck, keep at it.:2cents:

ok well first off, my dad owns the shop, and the truck is his but i use it. so the factor about being an atm is ok...lol. The fan needed to be changed, not having anything to do with the slipping. but believe me my dad is feed up with all the crap ive done to the truck so he always wants it fixed and out. also the truck is bone stock except for the intake and spacer i told u about, and a radio system pushing almost 1000watts with a capacitator. i guess i have to get moving on the timing and get that spacer out (back to square 1)....but do you think iv'e done too much damange to the motor by it being loud? oo and by the way the motor didnt suffer any power loss...even tho the tranny was slipping it still moved. im hoping its all good because at 162,000 she runs real good, plus its highly maintained. Thanks again i really appreciate your 2 cents!!

ok i replaced the clutch fan and the motor sounded fine. Then i took it for another spin when it was cold and i hit the gas, and it was real loud again. theres no spacer and the timing was lowered... maybe the fan cluth was a cheap one? what should i do now?

ok i replaced the clutch fan and the motor sounded fine. Then i took it for another spin when it was cold and i hit the gas, and it was real loud again. theres no spacer and the timing was lowered... maybe the fan cluth was a cheap one? what should i do now? i guess i will ask questions about what was the loud noise from the engine?
loud rumbling, loud exhaust, popping loud , has any fire or popping come out of the intake? does your dad have any idea what the noises are? you said he owned a shop, and the truck is well maintained, was it by your dad? if you bought a fan clutch that was a direct replacement for the engine, and installed correctly, it may not be a problem anymore. also, what type of intake did you put on it?
do you have access to a diagnostic trouble code reader?? if you can get any codes, gm website will tell you what they are, also someone here like blazee or old master may be willing to help. there are many others, but those are the 2 users that come to mind. it's hard to diagnose noises, power loss, etc. through a computer forum. :frown:

well it seems that the fan clutch acts up sometimes and its just loud (like heavy breathing) but its recently been fine with the spacer off and original lid on. anyway i need to check the codes like you said.. my dad said the injectors and something else on the confusing throttle body needed to be change beacause of rough starts and hiccups while driving. what would be a good throttle rebuild (eldebrock or holley..ect)or if i should get a good junk yard one?? could you or anyone else recommend me a good exhaust cause its starting to go ... thanks again