# Hesitates when cold



## kpa2 (Feb 10, 2005)

My 89 Max Se runs fine ... except when cold. For first 15 minutes when accelerating between 1000 to 2500 rpm it hesitates, bucks, bogs down, sputters ... than takes off like a rocket. I took car to shop to have work done on brakes and asked then to check this problem out also. They said they checked for vacuum leaks but could not find any. They said the computer might be bad but could not check computer because their machine cannot read my max codes. Any suggestions?


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## zguy (Sep 13, 2005)

kpa2 said:


> My 89 Max Se runs fine ... except when cold. For first 15 minutes when accelerating between 1000 to 2500 rpm it hesitates, bucks, bogs down, sputters ... than takes off like a rocket. I took car to shop to have work done on brakes and asked then to check this problem out also. They said they checked for vacuum leaks but could not find any. They said the computer might be bad but could not check computer because their machine cannot read my max codes. Any suggestions?


either take it some where they can read the codes or let it warm up before leaving.


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## alexnds (Oct 1, 2005)

*3rd Gen Maxima is OBD-I computer, not OBD-II*



kpa2 said:


> My 89 Max Se runs fine ... except when cold. For first 15 minutes when accelerating between 1000 to 2500 rpm it hesitates, bucks, bogs down, sputters ... than takes off like a rocket. I took car to shop to have work done on brakes and asked then to check this problem out also. They said they checked for vacuum leaks but could not find any. They said the computer might be bad but could not check computer because their machine cannot read my max codes. Any suggestions?


Engine codes for 3rd Gen OBD-I computer:
http://forums.********.com/zerothread?id=126534

Your car has OBD-I computer, not OBD-II, many shops can not read codes from the older OBD-I level system because their reader doesn't have the software necessary to read these codes. Use the link above to help you.


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## internetautomart (Mar 8, 2004)

probably a coolant temp sensor


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## kpa2 (Feb 10, 2005)

alexnds said:


> Engine codes for 3rd Gen OBD-I computer:
> http://forums.********.com/zerothread?id=126534
> 
> Your car has OBD-I computer, not OBD-II, many shops can not read codes from the older OBD-I level system because their reader doesn't have the software necessary to read these codes. Use the link above to help you.


Codes stored is 55 meaning normal operation. My emission test was due last week ... and it passed emission test. So now I think it may be plug wires, distributor cap or coil. Any feedback?


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## alexnds (Oct 1, 2005)

*car hesitates when cold?*



kpa2 said:


> Codes stored is 55 meaning normal operation. My emission test was due last week ... and it passed emission test. So now I think it may be plug wires, distributor cap or coil. Any feedback?


Your distributor cap and rotor have nothing to do with the car behaving badly at only a specific rpm range. If your ignition timing was off in any way, it would happen at ALL temperatures, and all different rpm ranges, not just when cold, or between 1,000-2,500 rpm. Your emissions test shows your CO and Nox was fine. It doesn't mean your car is in a good state of tune. It also doesn' mean that your fuel map, that tells the ratio of air-to-fuel how to behave at any given rpm is good either. It only means your exhaust is clean enough to pass emissions.

If you need to do a tune-up, then do a tune up. It may or may not in any way be related to your problem however, and I don't suspect it.

Once you've done a tuneup, as already mentioned, if it still happens, your coolant temperature sensor is the next step to check. Does the car shake when cold, or just sort of misfires? What are the symptomps of how it behaves? Does it happen at any particular rpm or at idle? If it happens between 1,000 rpm-2,500 rpm, while in gear, or you've done this with the car standing still and in park and taken it to that particular rpm range? Does it happen above 2,500 rpm, for example, 3,000 rpm to 5,500 rpm? You mention between 1,000-2,500 rpm, but is it when driving or in park?

If it happens at idle, your idle air control valve may be at fault. Your computer map, governing air-to-fuel ratio maybe at fault. Clean out your throttle body with seafoam,put some in the gas tank and some in the oil, and this should clean out any carbon buildup. Also, take off your EGR valve, use some carbeurator cleaner to get rid of the gunk, and re-install it. Once you've done all 3 things: (a)tuneup, (b)throttle body cleaning, (c)egr cleaning let us know if the symptoms are still there. At the least, doing a tuneup and getting rid of carbon deposits can't hurt.


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## DRUNKHORSE (Mar 6, 2005)

that does sound like a coolant sensor, but also the TPS and or the AICV. I would start by checking the plug wires first tho just because thats a 5 min check. then I would lean towards the TPS.


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