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I have an erratic idle going on

3K views 24 replies 4 participants last post by  94gtconvert 
#1 ·
My 94 gt has always idled like crap but it's getting hotter out and it seems to be worse when my rad fan kicks on, ac running, radio etc... So it has only stalled on me once last fall and I was wondering why I can do to fix this. It runs fine in the cold or when it's cold but when shes hot and I'm at a red light the rpm's are all over the place. Keep in mind the distributor is relatively new, new fuel filter , plugs. Thanks
 
#2 ·
Did you change wires with the plugs? I did plugs and not wires. Lost my spark, it ran but like poop. Check the iac? Tps I believe can do this too. Also have the alternator checked, when the fan kicks on it causes more load on the alternator and a loss of spark to the plugs will cause chappy idle.

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#7 ·
Inlet air temp sensor being flaky? Any aftermarket intake stuffs? Tstat good and fan kicking on in the right places? What actual temps are you running in the heat? If you don't have an aftermarket gauge I'd get one. I doubt its wires but new wires can just make the car run better in general if yours are old. PO of my 98 told me the wires were like 10 yrs old when I replaced them which made sense because the car ran a ton better afterwards.
 
#8 ·
I have water temp, oil pressure and trans temp jegs gauges in place of the stock CD player. She runs right around 185 degrees on a hot day. Fan only kicks on when I come to a stop or traffic. Never overheats. I used some brass fittings to tee off the factory sending units so my computer still knows temp and oil pressure . The past owner changed the wires like 6 years ago with scrappy duralast wires cap and rotor. Also I have a cold air intake witch has no vaccume leaks and Teflon tape on the inlet sensors threads

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#9 ·
I have done some more research and I found the 94/95's are natorius for distributor isseues. I poped my cap off and there was a nice amount of carbon built up on the caps contacts, and the rotors contacts was scored up. I cleaned them with brake cleen and sanded the contacts with very fine grit paper. Car still runs like crap. Can it be the pip sensor in the distributor, or the TFI control module? Again it died on be a while back and has come very close multiple times after, it always starts right back up like nothing happend, and is stable through every rpm just choppy at idle.

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#10 ·
I have this same erratic idle problem as soon as I'm at 1500 rpms or more it doesn't miss or anything and runs like a champ..... Mine hasn't died though since I capped the vacuum line that went to that ball under the drivers front fender.... Still sounds a little erratic but the rpms don't jump around and it stays cranked
 
#12 ·
U mean e303 ? And I'm not sure the exact name but if u cap It you'll still have a good vacuum and if that ball is cracked or leaking it'll be better.... Easy way to tell is crank your car and put your head by your front left tire.... If it's leaking you'll hear it ... Jus cap the line off and it'll help the idle surge too
 
#13 ·
I'm sure he means b303, common cam to use with the gt40s.
 
#14 ·
Yea b303, I will check the fender well because I hear what could be a vaccume leak from there but I thought it was my CAI. I seafoamed the car today I know I know very touchey soubject with people but belive it or not it made a world of a diffrencem I put it in through the vaccume line closest to the TB and let it sit for 10 mins after putting half a bottole through. It made a nice amount of some and idles way better.

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#15 ·
Make sure you do the oil asap after you seafoam it.
 
#19 ·
No, it'll get into the oil. Change immediately after the smokeshow subsides.
 
#17 ·
I'd still do it as soon as possible..you won't have to worry about a idling problem when your oil pump, cam and crank bearings crap out on ya. Just a word of advice. That stuff works good but any way you use it it'll find its way to the oil, thin it out, and then your screwed.

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#21 ·
Nope, the basic TFS/Crane single springs will be more than fine for what the stock block can handle. Just have the GT40s cleaned, valvejob, new valve seals/locks/springs/retainers and have the EGR bumps ground down which should take the shop all of a half hour.

Then send your GT40 lower out to tmoss (look up tmossporting on google) for the best GT40 portjob you'll ever get, put it all together, measure pushrod length for the B cam, order one piece hardened pushrods and then put it all together and fire it up at 10 degrees advanced. Make sure you have no leaks or anything, shut it down and tow it to a dyno tuner. Once tuned you should be sitting at 275-280 at the wheels with cleaned up GT40s/b303/ported intake. This will make for a 12 second car with the right suspension and 11s with a 125 shot easy.
 
#23 ·
I have no idea what he charges now, I had my GT40 done back in 2005 lol. Inflation and all...
 
#25 ·
What size injectors should I go with, also what brand fuel rails. And how many LPH should my new fuel pump have? I thinking of buying the aeromotive fuel dilivery kit with the rails, lines, fittings and regulator but it's like $700. Not including the pump or injecots lol
 
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