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Unread 04-05-2010, 02:16 PM   #1
cjapgar
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4 cyl engine issues

so within the last few days my engine has started running a bit raggedly.
The idle is at about 800, and both idle and neutral rev sound normal.
however when in gear, it is really choppy and i can relate it to the baseball card on a bike tire. Changed the plugs and nothin changed.

Gonna check the ignition coils as soon as i have the time.

what else should i be checking.
to clarify it is only noticeable when in gear.

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Unread 04-05-2010, 02:24 PM   #2
provinT13
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If it's only there when in gear I would start with the transmission, drive shafts, u joints, and t-case
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Unread 04-05-2010, 02:24 PM   #3
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See if you have any codes showing.
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Unread 04-05-2010, 02:25 PM   #4
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Is that the sound you hear coming from the exhaust or is it a clunking or ticking sound coming from the engine?
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Unread 04-05-2010, 02:28 PM   #5
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Quote:
Originally Posted by provinT13 View Post
If it's only there when in gear I would start with the transmission, drive shafts, u joints, and t-case
will be checking the tran fluid later, but what all should i be looking for there?

Quote:
Originally Posted by MJMPC View Post
See if you have any codes showing.
no codes but the non-existant ac

Quote:
Originally Posted by RebuildRookie View Post
Is that the sound you hear coming from the exhaust or is it a clunking or ticking sound coming from the engine?
well you can kind of feel it in the pedal, so i dont think its the exhaust, plus checked it out and it looks fine.

so update: checked out the ignition coil : primary was 1.9 high, and the secondary was 12.4 right on would the primary be causing this problem?
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Last edited by cjapgar; 04-05-2010 at 09:06 PM.. Reason: more info
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Unread 04-06-2010, 10:37 PM   #6
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so talked to a car guy and he said the ignition coil is fine, so i picked up wires and a fuel filter. The more i think about it i think its a fuel issue
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Unread 04-07-2010, 12:29 AM   #7
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I really don't see how something making a grinding and chattering noise can be a fuel issue if you're not getting any codes and your engine is running fine in neutral and at idle. Drain/change your trans and t-case fluid. Stick your finger in there and feel around for any metal or gunk that may have gotten in.
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Unread 04-11-2010, 10:10 PM   #8
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been diagnosing some more and can say its not the tranny, def either the fuel or ignition

its running real rough, and occasonally back fires, with lots of vibs from non ignited gas or somthing

if i dont get this soon ill have to hit up a shop
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Unread 04-12-2010, 05:34 AM   #9
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Grab an ohmmeter and check your sensors; make sure the coolant temp and IAT sensors are reporting the correct air and coolant temps to the ECM. If they are bad, your mixture will be way off and could cause these issues. The IAT should be around1-2K Ohms I believe, and the coolent temp should be under 1K on a warm engine .
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Unread 04-12-2010, 05:08 PM   #10
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how exactly do you go about testing those, my hanes book says "beyond the scope of the home mechanic"

can i just remove the wiring harness to see if the problem stops? and where exactly are these sensors?
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Unread 04-12-2010, 06:03 PM   #11
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was able to check the coolant sensor and cold it read 12 ohms, got dark before i could get to the iat
also tried running it without the iat hooked up and it ran pretty much the same
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Last edited by cjapgar; 04-12-2010 at 10:01 PM..
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Unread 04-16-2010, 10:57 AM   #12
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Bump...


10char
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Unread 04-16-2010, 11:09 AM   #13
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Either of the 2 sensors should measure around 1k-2k (ish), when warmmed up. I installed a 1.2K resistor in the iac harness until the sensor I ordered came in . The engine ran 95% perfect, (which was at least 50% better than before!). My original IAC sensor measured 300K, which said the temp was around -40F !
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Unread 04-16-2010, 11:17 AM   #14
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bad crank position sensor, bad map sensor, bad fuel injector
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Unread 04-16-2010, 11:38 AM   #15
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Does it run any different between cold and when its warmed up? Does it happen at idle or when you are accelerating? Backfiring and missing is a timing issue related to sensors. Make sure you read the right temp sensor. The one you want to read is in the front of the engine on the thermostat housing. Clean out your throttle body and your IAC.
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