# Hit a bump while driving, now ticking badly?



## Cholden130 (Mar 27, 2020)

I just bought a 91 4cyl Hardbody 4wd with 113k miles and drove it home. (about an hour and a half drive). The next day I took it out for drive and it ran fine. I pulled out of a gas station and hit a little bump and it started to tick very badly and had almost no power. No check engine light. It will start and idle just fine but sounds almost like a diesel all the way through the rpm's. Changed spark plugs and distributor cap because they looked rough, no change. I then removed the valve cover to check the timing chains tension because I suspected it may have jumped time or something and it seems very tight? Ive never experienced anything like this and any help would be appreciated. Thank you


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## jp2code (Jun 2, 2011)

Check the codes 






[VIDEO] Checking Error Codes - Infamous Nissan - Hardbody / Frontier Forums


[VIDEO] Checking Error Codes Hardbody Forum (D21)



www.infamousnissan.com





You could be in limp mode.


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## Cholden130 (Mar 27, 2020)

I checked the codes and got a 41 which I believe is an iat sensor. No other codes than that?


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## jp2code (Jun 2, 2011)

Cholden130 said:


> I checked the codes and got a 41 which I believe is an iat sensor. No other codes than that?


An Idle Air Temperature error will cause the ECU to go into limp mode. 

Take a look at this thread: 






Code 41 - Infamous Nissan - Hardbody / Frontier Forums


Code 41 Engine and Drivetrain



www.infamousnissan.com


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## Cholden130 (Mar 27, 2020)

Okay I just replaced the iat sensor and it didnt make any change? Very confusing as I cant find any information on a similar issue.


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## jp2code (Jun 2, 2011)

Cholden130 said:


> Okay I just replaced the iat sensor and it didnt make any change? Very confusing as I cant find any information on a similar issue.


A code does not always mean the sensor isn't working. It means the ECU is not getting the signal that it expects. You could have bad connections going to the sensor or a bad ground wire for the sensor.


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## Cholden130 (Mar 27, 2020)

Well the wires were broken off for the sensor and it wasnt plugged up to anything so it wasnt functioning so I'm not sure. I also just did a compression test just to see and all cylinders are between 70-80 it ran great before this and still doesnt smoke or anything.


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## jp2code (Jun 2, 2011)

Cholden130 said:


> Well the wires were broken off for the sensor and it wasnt plugged up to anything so it wasnt functioning so I'm not sure. I also just did a compression test just to see and all cylinders are between 70-80 it ran great before this and still doesnt smoke or anything.


What, you think hitting a bump is going to knock out the compression in your engine? 70 to 80 seems low, but that is for a different discussion. 

More likely hitting a bump made the corroded wires lose contact.


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## Cholden130 (Mar 27, 2020)

No I'm fully aware that hitting a bump didnt make me loose compression.. It is a valid point to bring up considering that is only around half or so of what it should have. However the IAT didnt have anything to do with the issue as ive replaced it. It's throwing no codes now so I'm leaning towards it being a mechanical issue, it sounds mechanical for sure.


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## jp2code (Jun 2, 2011)

Gotcha. I'm trying to diagnose based on common failure reasons.


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## Cholden130 (Mar 27, 2020)

Thank you for helping me narrow it down. I can't imagine what could cause this strange scenario and unfortunately I'm an amateur at diagnostics. Also when I took off the valve cover there was a broken cylindrical (about the size of a quarter in diameter and about an inch long) piece of plastic laying near the rocker arms. Doesnt seem to be a piece of tensioner or guide, considering they look to be intact.


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## jp2code (Jun 2, 2011)

There are valve guides and seals that break, but that isn't very common. 

Can you take and post a picture of it with your phone?


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