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Old 03-23-2012, 01:06 PM
green94mtx green94mtx is offline
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Default 94 mtx hesitation/lugging/cutting out below 4k

I did a search and couldn't find much, When i'm accelerating, it cuts out/lugs/hesitates mostly from 2500-3500 rpm. WHat could this be? Doesn't matter if i'm 1/2 throttle or WOT. Doesn't seem to happen below 1/2 throttle though (light acceleration). New crank sensor, new plugs, new intake & TB gaskets. Tried another used MAF and that didn't do anything, i cleaned it very throughly too. Any info would be greatly appreciated. Thanks
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Old 03-23-2012, 02:07 PM
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pull the codes first.

my guess is that the tps is bad, but you need to pull the codes rather than guess.
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Old 03-23-2012, 02:51 PM
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Will do. I will let you know what i find. No CE light, but it's worth a try!
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Old 03-23-2012, 02:57 PM
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KOEO and KOER tests. Pull codes.
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Old 03-23-2012, 03:05 PM
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Quote:
Originally Posted by green94mtx View Post
Will do. I will let you know what i find. No CE light, but it's worth a try!
Just because there is no CEL, doesn't mean there aren't any codes...
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Old 03-23-2012, 03:26 PM
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Quote:
Originally Posted by Vnuk1 View Post
Just because there is no CEL, doesn't mean there aren't any codes...
THat's why i said it's worth a try lol
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Old 03-23-2012, 07:11 PM
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These are the 2 codes
122 Throttle Position Circuit lower than minimum volt.
157 Mass Air Flow Circuit lower than minimum volt.
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Old 03-23-2012, 07:44 PM
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Unplug your MAF and drive it with it unplugged.
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Old 03-23-2012, 08:07 PM
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Quote:
Originally Posted by Vnuk1 View Post
Unplug your MAF and drive it with it unplugged.
What good will that do me?
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Old 03-23-2012, 10:25 PM
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Don't ask questions, just do it.
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Old 03-23-2012, 10:38 PM
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Quote:
Originally Posted by Vnuk1 View Post
Don't ask questions, just do it.
I unplugged the MAF before starting the car. CEL immediately came on. Started driving and it ran how it was supposed to! I was able to go 30mph in 3rd and give it roughly 3/4 throttle and it accelerated with no cutting out at all! Then drove another mile or so and it started doing it again....... ugh ******* SHOs
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Old 03-23-2012, 11:54 PM
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When you replaced the MAF with another are you sure of its being a known working sensor? Do you have a known working TPS to swap in?

Last edited by Vnuk1; 03-23-2012 at 11:56 PM.
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Old 03-24-2012, 12:04 AM
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Well i bought it at a junkyard for $15... So, i'm not sure on that one. And i do not..
They're not too expensive. Should i try metering the voltage?
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Old 03-24-2012, 12:05 AM
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ok, so either the tps is bad, or the ground to the circuit is bad - the tps and the mafs share the same circuit, and since both are being reported as bad it suggests a ground or power issue.

trace the wiring and make sure all connections are good, especially the ground. if that doesn't do any good, then replace the tps, reset the codes, and try again.
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Old 03-24-2012, 12:09 AM
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Do what he said and check your wires first, maybe you have a fubared wire or ground.
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Old 03-24-2012, 12:19 AM
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THanks guys. I'll keep you updated
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Old 03-27-2012, 07:19 PM
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Bought a new TPS just to see, and it didn't change anything. And i unplugged the MAF and it didn't change anything. Must've been a coincidence the other day. Where can i find the ground for that circuit?
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Old 04-09-2012, 04:12 PM
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Where can i find the ground for that circuit? Still driving the car this way..........
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Old 04-13-2012, 02:05 PM
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Update on SHO issues. The new TPS got rid of the 122 code. The 157 MAF code is still there. And now i have a new code 214. And still dealing with the severe bucking under acceleration. Unplugging the MAF doesnt do anything. But now that 214 Code bring me to think Cam Sensor? Crank sensor was done last year along with aux wire from DIS to negative terminal. Any info would be greatly appreciated. Thanks guys.

I have a spare DIS i might try since its easy. Also, i heard i can unplug cam sensor and drive it that way just without a tach (and may take several times to start) thoughts?
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Old 04-13-2012, 03:37 PM
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Hows your fuel pressure?

Check to see how well your DIS is grounded and try re-gooping the back with di-electric compound also making sure the connectors are making contact.
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Old 04-13-2012, 06:48 PM
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You may have a vacuum leak. I would get some spray starting fluid, start the car and while it is idling spray around the intake between the air cleaner to the intake manifold. If the idle jumps up, that is where your vacuum leak is. I had a similar problem that was caused by crack in the pipe between the MAF and throttle body.

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Old 04-13-2012, 06:59 PM
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Quote:
Originally Posted by jedhead View Post
You may have a vacuum leak. I would get some spray starting fluid, start the car and while it is idling spray around the intake between the air cleaner to the intake manifold. If the idle jumps up, that is where your vacuum leak is. I had a similar problem that was caused by crack in the pipe between the MAF and throttle body.

Bob
I replaced ALL intake gaskets and recently inspected intake hose. All is good. I've also already done the carb cleaner/starting fluid test with no results. It did this before and after replacing the gaskets btw
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Old 04-14-2012, 06:06 PM
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Unplugged the cam sensor and it didn't change anything. I pulled the DIS module and cleaned everything up and put di-electric compound on it. And have a good ground for the DIS as well. I have a spare DIS, should I try that next? Btw I still have the maf code as well
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Old 04-15-2012, 11:30 PM
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Update, spare DIS didnt change anything. Is it possible that the wiring going to the connector plugs for the DIS are bad?
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Old 04-17-2012, 09:37 PM
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Update on my 94 mtx. Backfires alot when taking off from a stop (have to ride the clutch a bit, to prevent this), Stumbles severly when accelerating, tach does NOT drop, only stumbles under 4000 rpm (still seems a bit underpowered after 4k, but runs how it should), unplugged cam sensor and nothing changed, unplugged MAF and nothing changed, crank sensor is less than a year old and properly gapped, brand new TPS, good ground to DIS and also tested good, still have intermittent codes 157 & 214. Ground at intake is good. Just reset the codes today and went for a drive, same 2 are coming back. Please help guys.. I'm getting desperate here.
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Old 04-24-2012, 01:29 PM
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Ended up being plug wires... I was so hung up on what the codes were.. I feel dumb haha, thanks for the help guys!!
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  #27  
Old 04-24-2012, 04:31 PM
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Glad you found it. :D Sometimes its the simple things we tend to overlook the most
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