# 1996 F150 4.9l running rough when hot

**URL:** <https://community.cartalk.com/t/1996-f150-4-9l-running-rough-when-hot/106658>\
**Category:** Maintenance/Repairs\
**Tags:** ford\
**Created:** [August 6, 2017, 12:12pm UTC](https://community.cartalk.com/t/1996-f150-4-9l-running-rough-when-hot/106658 "2017-08-06T12:12:40Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![r4448](https://avatars.discourse-cdn.com/v4/letter/r/8edcca/32.png) [@r4448](https://community.cartalk.com/u/r4448)\
**Post date:** [August 6, 2017, 12:12pm UTC](https://community.cartalk.com/t/1996-f150-4-9l-running-rough-when-hot/106658/1 "2017-08-06T12:12:40Z")

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I have a 1996 Ford truck with a 4.9L engine that after warming up the engine runs really rough.  
When I drive like this I can get it to run better after driving a while. But,  
if it sits for a while it will start right up and run good until I shut it  
off again. I get two codes 0171 and 0174 which engine runs too lean in bank 1  
and 2.  
I change the distributor, ignition coil and ECM for ignition .  
Replaced EGR and EGR solenoid, idle control module, MAF sensor, thermostat, temp  
sensor for computer and engine, hotter spark plugs, replaced injectors, and  
all 3 oxygen sensors. Please help

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**Author:** ![COROLLAGUY1](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/corollaguy1/32/7575_2.png) [@COROLLAGUY1](https://community.cartalk.com/u/COROLLAGUY1)\
**Post date:** [August 6, 2017, 2:19pm UTC](https://community.cartalk.com/t/1996-f150-4-9l-running-rough-when-hot/106658/2 "2017-08-06T14:19:02Z")

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What is the milage? Did you get a compression test?

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**Author:** ![insightful](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/insightful/32/2732_2.png) [@insightful](https://community.cartalk.com/u/insightful)\
**Post date:** [August 6, 2017, 7:32pm UTC](https://community.cartalk.com/t/1996-f150-4-9l-running-rough-when-hot/106658/3 "2017-08-06T19:32:03Z")

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> [@r4448](#):
>
> hotter spark plugs

Why?..were the ones you took out black?

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**Author:** ![r4448](https://avatars.discourse-cdn.com/v4/letter/r/8edcca/32.png) [@r4448](https://community.cartalk.com/u/r4448)\
**Post date:** [August 6, 2017, 9:55pm UTC](https://community.cartalk.com/t/1996-f150-4-9l-running-rough-when-hot/106658/4 "2017-08-06T21:55:07Z")

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Yes I did a compression test and the range was 156 to 160 per cylinder. The mileage is 277,576 miles.

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**Author:** ![r4448](https://avatars.discourse-cdn.com/v4/letter/r/8edcca/32.png) [@r4448](https://community.cartalk.com/u/r4448)\
**Post date:** [August 6, 2017, 9:58pm UTC](https://community.cartalk.com/t/1996-f150-4-9l-running-rough-when-hot/106658/5 "2017-08-06T21:58:16Z")

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There was no real reason, I was trying anything.  
The spark plugs I took out were in good shape and white.

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**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\
**Post date:** [August 6, 2017, 11:35pm UTC](https://community.cartalk.com/t/1996-f150-4-9l-running-rough-when-hot/106658/6 "2017-08-06T23:35:33Z")

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Have you tested the fuel pressure?

Especially the residual fuel pressure?

Tester

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**Author:** ![r4448](https://avatars.discourse-cdn.com/v4/letter/r/8edcca/32.png) [@r4448](https://community.cartalk.com/u/r4448)\
**Post date:** [August 7, 2017, 2:02am UTC](https://community.cartalk.com/t/1996-f150-4-9l-running-rough-when-hot/106658/7 "2017-08-07T02:02:29Z")

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no, I have not tested the fuel pressure or residual fuel pressure. where do I do that at? Thanks