Juanhmi
Elite Explorer
- Joined
- June 16, 2020
- Messages
- 58
- Reaction score
- 44
- City, State
- Louisville
- Year, Model & Trim Level
- '99 XLS V6 OHV
Been getting steadily worse fuel mileage on my '99 OHV, down to 10-11 in town. I've been all over looking for vacuum leaks and I don't think I have any, or any bad intake gaskets, although the carb cleaner trick might just not be hitting the right spot. New MAF sensor, new air filter, new PCV valve, I "think" I replaced the idle air control valve a year or two ago but can't remember. Long term fuel trim at idle on both banks is +7-10%, scan indicates a "pending" lean code on both banks but hasn't tripped a check engine light yet.
At 237,000 miles I'm wondering about O2 sensors. They seem easy to reach and aren't terribly expensive, but I could also be missing something real dumb. Aside from this being a really hard-to-find vacuum leak, am I missing anything?
I did just have valve cover gaskets done by a shop I trust and I've taken a look at any hoses they could have knocked loose. If I can't figure it out myself I'll take it into them, but I'm not blaming them yet as the fuel consumption issue has been going on since before that job.
Edit: fuel filter is also less than a year old. I have not read fuel pressure yet, need to buy a gauge (I have one but for low pressure carbureted vehicles only).
At 237,000 miles I'm wondering about O2 sensors. They seem easy to reach and aren't terribly expensive, but I could also be missing something real dumb. Aside from this being a really hard-to-find vacuum leak, am I missing anything?
I did just have valve cover gaskets done by a shop I trust and I've taken a look at any hoses they could have knocked loose. If I can't figure it out myself I'll take it into them, but I'm not blaming them yet as the fuel consumption issue has been going on since before that job.
Edit: fuel filter is also less than a year old. I have not read fuel pressure yet, need to buy a gauge (I have one but for low pressure carbureted vehicles only).