2002 XLT... hesitates and loses thrust when going uphill on highway...

[ignorantmonkey]

I have noticed my truck which is a 2002 XLT 4.6 ...some 145K miles...has some issues when I drive at 65-80MPH uphill on highways. When it runs on straight roads has zero issues, it is just when the road goes uphill...no matter how much uphill goes, so it starts hesitating, I can feel it having trouble and seizure-like loss of regular power....so when it does that I just pull out my foot off the accelerator pedal, and then I go in again...but the issue corrects when the road gets even again... I have serviced the injectors, changed the air and fuel filters, the oil and spark plugs recently...even the throttle body assembly has been cleaned with carb cleaner spray.... Any ideas on what could be wrong?

 

[american steel]

codes?
fuel pump
PCM (rare but it has happened)
PCV hoses.
noises?
AWD? trans issue when going uphill (extra load on engine sensors detect this goes to PCM)
sensors. 1 or more
fuel pump

 

[ignorantmonkey]

codes?
fuel pump
PCM (rare but it has happened)
PCV hoses.
noises?
AWD? trans issue when going uphill (extra load on engine sensors detect this goes to PCM)
sensors. 1 or more
fuel pump

Went to Auto Zone and they ran 3 different codes:
P0132, P1131 and P0172.

P0132 says is an oxygen sensor heating. Bank 1, Sensor 1.

P1131 says Fault at transition of 02 on bank 1.

P0172 says Readjustment conditions of fuel on Bank 1.

No idea what these might mean...

 

[05expedeb]

Sending you a pm

 

[Evil_by_Birth]

Same Issue

Was a resolution to this ever found? I just purchased a 98 Expy EB 4x4 and its doing the exact same thing.

 

[WPG2013]

Had a similar issue with my 99, turned out to be the fuel pump. Ran fine on level ground, but began to stumble on hills.

 

[AbbadonTD]

o2 sensor is usually the culprit on these "struggling" issues.

 

[BAD RONALD]

I had problems with my '01 similar to this with no codes recorded.

The truck ran like crap under load, but especially so on rainy and damp days.

I changed the COP's with the cheapest replacements I could find on Ebay. Coated the COP boots generously with dielectric grease inside where the spring connector is located. End of misfires, problems under load and poor running in damp weather.

It's likely that the COP's themselves on my truck were OK. I didn't know any better at the time. Could've been that one (or more) COP boots on my truck were shot and the new boots that came with the replacements (when appropriately greased) cured the misfires. Importantly, my truck was misfiring without codes present.

COP boots are cheap. Old originals need to be inspected and properly replaced if necessary. Should be a regular maintenance check on these engines anyway.

Be great if an easy to fix unread condition turned out to be the source of the problem, no?

 

[Evil_by_Birth]

Great advice both of you. Thank so much. Maybe this weekend I can get my ride running right.

 

[Evil_by_Birth]

Its working!!

So it took alot more than a weekend. I'm not the most adept when it comes to engine work. However I replaced all of my coil boots and shrouds, as well as coil 5. It was in bad shape. I went ahead and replaced both o2 sensors and I ended up having an issue with my vehicle speed sensor so I replaced that as well. Now I'm running like a champ. Thanks again everyone for all of the advice.

 

[ignorantmonkey]

Was a resolution to this ever found? I just purchased a 98 Expy EB 4x4 and its doing the exact same thing.

No solution so far....I travel often and take same highway back and forth...and truck loses, say perhaps 50% of all its power/speed when starts to go uphill....