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Old 08-25-2010, 02:22 PM   #1
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350 tpi stumble rough idle

Just changed my plugs car fires up right away on like one crank now but stumbles and struggles to iddle keeps trying to die but doesnt. What could be the problem i need help fast pleaseeee
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Old 08-25-2010, 03:16 PM   #2
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Re: 350 tpi stumble rough idle

Have you try resetting the IAC motor? What reading do you have on the TPS at idle? What is your base timing? Have you ever removed and cleaned off the IAC motor? They can get quite a bit of carbon build up on them that will effect their ability to operate properly.
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Old 08-25-2010, 05:01 PM   #3
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Re: 350 tpi stumble rough idle

Im brand new to this engine dont know where anything is. I have no idea where timing is set. Where is the iac motor so i can check in and clean it.
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Old 08-25-2010, 05:18 PM   #4
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Re: 350 tpi stumble rough idle

just found a nice vacuum leak i think that might b the problem
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Old 08-25-2010, 07:41 PM   #5
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Re: 350 tpi stumble rough idle

i would check the iac like sharkbait said and then the map sensor vacuum connection if you are speed density.
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Old 08-25-2010, 07:45 PM   #6
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Re: 350 tpi stumble rough idle

is the iac under the plenum? do i have to remove the plenum to get to it? or can i get it without removing the plenum.
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Old 08-25-2010, 09:00 PM   #7
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Re: 350 tpi stumble rough idle

its on the pass. side of the throttle body under the tps sensor. theres a square 4 wire plug going to it.
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Old 08-25-2010, 09:26 PM   #8
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Re: 350 tpi stumble rough idle

I will check it out in the morning i have to take care of a vacuum leak i found. All the lines are old so i may just replace them all. Maybe the vacuum leak is whats been causing my car to run realy rich
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Old 08-26-2010, 11:41 AM   #9
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Re: 350 tpi stumble rough idle

i dont see any bolts to remove the aic
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Old 08-26-2010, 11:49 AM   #10
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Re: 350 tpi stumble rough idle

There aren't any bolts, it's threaded. Just unscrew it.
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Old 08-26-2010, 12:08 PM   #11
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Re: 350 tpi stumble rough idle

Mine was siezed up pretty good. I found it necessary to remove the throttle body to get a wrench on it and apply the proper leverage to break it loose.
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Old 08-26-2010, 12:37 PM   #12
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Re: 350 tpi stumble rough idle

That's what I had to do to mine.
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Old 08-26-2010, 01:43 PM   #13
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Re: 350 tpi stumble rough idle

Looks like ill probably have to do that also. Hopefuly the iac is the problem. Just fixed the vacuum leak and still doing it.
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Old 08-26-2010, 02:39 PM   #14
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Re: 350 tpi stumble rough idle

sorry didnt fix vacume need to replace the long line that leads to by the right headlight its worn to hell and if i move it where it connects near the passenger rear side of the plenum i can hear air escaping. Also do i need to drain coolant to remove the throttle body? because i cant get anything arround the iac to even start turning it.
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Old 08-26-2010, 02:42 PM   #15
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Re: 350 tpi stumble rough idle

took it for a spin arround the block before i noticed the second vacuum leak felt a little weak and stubled at stops but not getting any check engine lights
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Old 08-26-2010, 02:44 PM   #16
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Re: 350 tpi stumble rough idle

You might wanna make sure you didnt crack a plug when you were putting them in. This is how i actually got my car. The PO had installed a new set of plugs and cracked one putting it in, he coudldnt figure out why it wouldnt run right and invested alot of money in random new parts trying to figure out the problem. He never checked the plugs since he had just put new ones in and eventually got frustrated and sold it to me dirt cheap. First thing i did when i got it home was check the plugs, Bingo, 3rd plug back on drivers side was visibly cracked looking at it from under the car

At least check
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Old 08-26-2010, 02:48 PM   #17
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Re: 350 tpi stumble rough idle

well i just changed the plugs because of the problem so and before i changed them i was having starting issues but she fires right up now and fir about 5 seconds idles at like 1k then drops and starts to have trouble
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Old 08-26-2010, 03:53 PM   #18
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Re: 350 tpi stumble rough idle

When you drove the car did it have a thumpy pickup?
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Old 08-26-2010, 03:58 PM   #19
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Re: 350 tpi stumble rough idle

nope it moved without hesitation. Its not driving like its not getting spark or enough fuel. But it is even richer then it was before i changed my plugs
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Old 08-26-2010, 04:04 PM   #20
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Re: 350 tpi stumble rough idle

Do you have tpi or tbi?
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Old 08-26-2010, 04:06 PM   #21
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Re: 350 tpi stumble rough idle

now that i think about it when i opened it up while already moving it didnt take off like it normaly would felt a little hesitant
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Old 08-26-2010, 04:07 PM   #22
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Re: 350 tpi stumble rough idle

5.7 350 tpi
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Old 08-26-2010, 04:14 PM   #23
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Re: 350 tpi stumble rough idle

I had a back fire problem with my tpi, did you try checking the egr valve? Ive heard that can make a car backfire and have a bad idle shake
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Old 08-26-2010, 04:17 PM   #24
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Re: 350 tpi stumble rough idle

havent yet but i dont have backfires just idle surges and shakes at arround 500 to 800
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Old 08-26-2010, 06:15 PM   #25
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Re: 350 tpi stumble rough idle

i actually have the exact same problem, starts right up stays at about 1thousand RMP and drops between 5-700 rpm and the back end starts to shake. i havent been able to figuer out what it might be yet, but any help would be greatly apreciated
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Old 08-27-2010, 03:06 AM   #26
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Re: 350 tpi stumble rough idle

my back end doesnt shake just my engine and front end.
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Old 08-27-2010, 07:20 AM   #27
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Re: 350 tpi stumble rough idle

what does your volt gauge say when this happens. unplug est wire does it run a little smoother. Ive been chasing the same problem for the better part of this year.
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Old 08-27-2010, 01:19 PM   #28
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Re: 350 tpi stumble rough idle

i dont have a volt guage and whats the est wire and where is it. Sorry im completely new to this.
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Old 08-28-2010, 12:45 AM   #29
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Re: 350 tpi stumble rough idle

Try cleaning/replacing your O2 sensor, it's always a good thing to do when you replace the plugs, just another routine maintenance item that gets left out.
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Old 09-03-2010, 06:31 PM   #30
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Re: 350 tpi stumble rough idle

havent checked the 02 sensor but i just cleaned the iac and did the throttle body coolant bypass. and still idleing like **** and gets worse when i put it in gear
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Old 09-03-2010, 06:43 PM   #31
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Re: 350 tpi stumble rough idle

I am still having the same problem and i have no codes that show, do you have any codes?
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Old 09-03-2010, 06:45 PM   #32
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Re: 350 tpi stumble rough idle

i have a check engine light but dont have a scanner or 90 bucks to pay a shop to scan it.
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Old 09-03-2010, 06:49 PM   #33
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Re: 350 tpi stumble rough idle

Try doing the paperclip trick
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Old 09-09-2010, 08:50 PM   #34
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Re: 350 tpi stumble rough idle

whats the paperclip trick?
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Old 09-09-2010, 08:57 PM   #35
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Re: 350 tpi stumble rough idle

Alright basically if you no where your A and B ports are under the dash you stick one part of the paper clip in the A port and the other end in the B port. The A and B port are to the right and on the top the first two right next to each other. Heres a link that explains it better http://www.thirdgen.org/techboard/te...lip-trick.html (paperclip trick?) Here is the A and B ports http://tunertools.com/vendorinfo/obd1pinout2.gif
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Old 09-09-2010, 08:58 PM   #36
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Re: 350 tpi stumble rough idle

Let me know if you still dont get it after you read everything.
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Old 09-09-2010, 09:39 PM   #37
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Re: 350 tpi stumble rough idle

where is the ecm fuse i want to clear my computer after changing my plugs and cleaning my iac before i pull the codes to see whats wrong.
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Old 09-09-2010, 10:04 PM   #38
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Re: 350 tpi stumble rough idle

It should be right by your battery, look at the first picture. Its in a black cover and you have to open and the fuse is inside. http://www.thirdgen.org/techboard/el...e-problem.html (ECM Fuse Problem)
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Old 09-13-2010, 03:30 PM   #39
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Re: 350 tpi stumble rough idle

so i cleared my codes and started her to try and use the paperclip trick but now she wont throw any codes but when i rev her to 2 or 3 k im getting sweet smelling smoke from the exhaust and still idling realy rough then if i put it in drive car starts to shake and jump and just dies out. But never throws a code and when i use the paperclip all i get is the 12 the it starts with.
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Old 09-13-2010, 03:43 PM   #40
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Re: 350 tpi stumble rough idle

Alright i might have found my problem, a bad coil. Test all you spark plugs by removing the spark plug and once its out plug it into the wire and have someone start the car and obviously have a pair of pliers with the rubber grip and hold it to the exhaust manifold while someone start the car. It should be a powerful and blue spark
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Old 09-13-2010, 03:50 PM   #41
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Re: 350 tpi stumble rough idle

sht it takes so long to get most of those plugs out
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Old 09-13-2010, 03:56 PM   #42
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Re: 350 tpi stumble rough idle

Well for the start test cylinder #1 and tell me how that goes.
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Old 09-13-2010, 04:04 PM   #43
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Re: 350 tpi stumble rough idle

which cylinder is nnumber 1
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Old 09-13-2010, 04:20 PM   #44
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Re: 350 tpi stumble rough idle

The one on the drivers side closest to the front. Drivers side first one in the front
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Old 09-13-2010, 04:28 PM   #45
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Re: 350 tpi stumble rough idle

i dont think i remembered to point out this whole problem im having happened after driving thru a deceptively deep puddle. It was deep enough that i saw steam from the water getting onto the hot engine comming from my hood.
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Old 09-13-2010, 04:55 PM   #46
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Re: 350 tpi stumble rough idle

Most likely you have an electrical problem. I would check cylinder 1 spark.
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