Codes 172, 136 | Ford Explorer - Ford Ranger Forums - Serious Explorations

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Codes 172, 136


Well-Known Member
February 15, 2006
Reaction score
City, State
Kaysville, utah
Year, Model & Trim Level
94 XLT
I'm tinkering with a new (to me) 94 Exp with 172K miles on it, no mods, totally stock. The CEL seems to come on after Overdrive (or the tcc) engages - that is, easy on the throttle and rolling about 40-45 mph, or when pushing it up to freeway speeds. Shutting the engine off resets the CEL. No light again until rolling above 40mph.

KOEO code 111
CM codes 172,176
KOER codes 172,136

There's a ton of info for these codes on the forum, but I'm just looking for something I may have missed. I've checked for vacuum leaks - fairly confident there are none after doing a few repairs. Carb cleaner sprayed around reveals no increase in RPM. MAF looked clean, but sprayed MAF cleaner on it anyway. Replaced dirty air filter. It seems to me it's not running rich, no black smoke or smell. However, probably unrelated, the throttle body was extremely dirty and had a thick layer of some tar-like stuff on it. It was cleaned with TB cleaner, but the plenum is coated too. The O2 sensors and wires look OK visually.

On the plan is to check Fuel pressure, clean IAC valve, and remove O2 sensors to do the propane check.

Anything else?