Car randomly cuts out and bucks
Jun 12, 2012, 08:15 AM
#1
Evolving Member
Thread Starter
Car randomly cuts out and bucks
This may have already been discussed on the forums so if it has, my apologies. 
To be fair, I did try and search it beforehand.
My car under WOT will hesitate. Tends to happen most frequently around 2-3k RPM's. I've tried to replace everything I can think of to deal with the engine management system. Spark plugs, coil packs, wires, it still seems to do it.
It has occasionally thrown the P0340 CRANKSHAFT Position Sensor, the same error that causes the car to crank without actually starting. Here is something I noticed last night that may be the cause of it, me thinks.
I was cleaning the engine bay a little bit and behind the valve cover near the alternator is a grey plug that was absolutely covered by the typical oil/dirt sheet. I cleaned off the plug and when I wiggled it around, I heard something happen in the electrical system. I can't really describe it, but it responded to my touch. I am thinking that the leaking oil is messing with the plug that goes into the timing cover that connects into the crankshaft position sensor itself, not the sensor. I felt a bit more power from the car and 0 hesitation through the entire rev range through all of the gears. It would be nice since the car seems to have lost a dahmn lot of power. Ideas? Are my theories crazy, or actually plausible? No codes are there besides her lovely P0421 front $500 catalytic converter replacement.
To be fair, I did try and search it beforehand. My car under WOT will hesitate. Tends to happen most frequently around 2-3k RPM's. I've tried to replace everything I can think of to deal with the engine management system. Spark plugs, coil packs, wires, it still seems to do it.
It has occasionally thrown the P0340 CRANKSHAFT Position Sensor, the same error that causes the car to crank without actually starting. Here is something I noticed last night that may be the cause of it, me thinks.
I was cleaning the engine bay a little bit and behind the valve cover near the alternator is a grey plug that was absolutely covered by the typical oil/dirt sheet. I cleaned off the plug and when I wiggled it around, I heard something happen in the electrical system. I can't really describe it, but it responded to my touch. I am thinking that the leaking oil is messing with the plug that goes into the timing cover that connects into the crankshaft position sensor itself, not the sensor. I felt a bit more power from the car and 0 hesitation through the entire rev range through all of the gears. It would be nice since the car seems to have lost a dahmn lot of power. Ideas? Are my theories crazy, or actually plausible? No codes are there besides her lovely P0421 front $500 catalytic converter replacement.
Jun 12, 2012, 08:43 AM
#2
Off the top of my head I would say double check the gap on all your plugs and maybe even lower the gap a little to see if that helps. unclip that grey connector and check to make sure all the pins are still seating inside the plastic housing. I had an mr2 come to me once no spark. Come to find out one of the pins inside the connector going to the distributor has slid out far enough to not make connection. also clean inside it if its dirty in there and check for cracks or breaks in the wires shielding. Have you tried running any injector cleaner through? could be fuel related as well.
Last edited by 03lances; Jun 12, 2012 at 08:45 AM.
Jun 12, 2012, 11:41 AM
#3
Evolving Member
Thread Starter
I have ran 2 bottles (1 per fillup) of Sea Foam Motor Treatment in the tank. I can't really tell if it's actually doing anything or just the seat of the pants evaluation. :/ I was debating on replacing them until I found out how much they cost. $180 per injector from the dealer. What are they made of: unicorn horn alloy? :P
Jun 13, 2012, 04:25 PM
#5
Evolving Member
Thread Starter
The issue is getting worse. I can't apply any sort of acceleration without it bucking under acceleration. When in 2nd gear under 4,200 RPM's, I can apply a little acceleration and the tachometer will jump to 4,500, even though the speed of the car or the motor don't correlate. It leads me to believe that it is something electrical. It doesn't idle smoothly anymore and sounds like it wants to die. Unfortunately there is no codes attached to this issue, so I am lost.
Jun 14, 2012, 05:50 AM
#7
Evolving Member
Thread Starter
I don't, but I have heard of a similar device for testing fuel injectors. I see that Harbor Freight has them available for about $10. Hmm....
However I'm going to take it to my friends' mechanic shop, and have a professional check it out for me because I can't figure it out and it'll be cheaper than throwing parts at it (in both ways :P)
However I'm going to take it to my friends' mechanic shop, and have a professional check it out for me because I can't figure it out and it'll be cheaper than throwing parts at it (in both ways :P)
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Jun 14, 2012, 09:40 AM
#8
Evolving Member
Thread Starter
So I took it to my friends mechanic shop for the surging. They already knew I had the catalytic converter code that I'm taking care of. Turns out they found back pressure within the exhaust system. How much? The mechanics' gauge only goes to 15 PSI. He couldn't insert it into the second oxygen sensor because it was rusted in there, and he didn't want to break the sensor. So he measured it at the first one.
As I stated, it only goes to 15. It went to 15 PSI, snapped the PIN, went around again and broke. It broke the gauge lmao. He also stated that the second catalytic converter may be bad due to the severity of the first one. I wouldn't be surprised.
As I stated, it only goes to 15. It went to 15 PSI, snapped the PIN, went around again and broke. It broke the gauge lmao. He also stated that the second catalytic converter may be bad due to the severity of the first one. I wouldn't be surprised.
Jun 15, 2012, 04:38 PM
#13
Evolving Member
Thread Starter
The camshaft position sensor seems easy enough to replace, but what about the crankshaft position sensor? It's right above the crankshaft and held on by 2 10mm bolts, is that correct?