# Diagnosis puzzler **URL:** \ **Category:** General Discussion\ **Created:** [September 8, 2023, 11:00pm UTC](https://community.cartalk.com/t/diagnosis-puzzler/192756 "2023-09-08T23:00:15Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [September 8, 2023, 11:00pm UTC](https://community.cartalk.com/t/diagnosis-puzzler/192756/1 "2023-09-08T23:00:15Z")
Ok, I already know the answer, but feel free to make your guess. Modern configured but older car seems to have suddenly and for no clear reason lost much of its engine power and engine is misfiring so badly it is nearly un-driveable. New MAF, new fuel filter, no vacuum or exhaust leaks, new throttle position sensor. Same problem. Wiring, grounds all ok. Scan tool diagnosis shows nothing wrong, injectors injecting fine. ---
**Author:** ![bing](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bing/32/4619_2.png) [@bing](https://community.cartalk.com/u/bing)\ **Post date:** [September 9, 2023, 12:14am UTC](https://community.cartalk.com/t/diagnosis-puzzler/192756/2 "2023-09-09T00:14:41Z")
Diesel in the gas. ---
**Author:** ![asemaster](https://avatars.discourse-cdn.com/v4/letter/a/5f9b8f/32.png) [@asemaster](https://community.cartalk.com/u/asemaster)\ **Post date:** [September 9, 2023, 12:17am UTC](https://community.cartalk.com/t/diagnosis-puzzler/192756/3 "2023-09-09T00:17:17Z")
Distributor leaking oil internally into the cap. > [@George\_San\_Jose1](#): > > Modern configured but older car Seriously George, need a bit more info. Would this happen to be a 92 Corolla? ---
**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\ **Post date:** [September 9, 2023, 1:23am UTC](https://community.cartalk.com/t/diagnosis-puzzler/192756/4 "2023-09-09T01:23:02Z")
Completely worn out engine… But I need more information, you know the drill… Year, make. model, miles, engine… ---
**Author:** ![davesmopar](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/davesmopar/32/41750_2.png) [@davesmopar](https://community.cartalk.com/u/davesmopar)\ **Post date:** [September 9, 2023, 2:15am UTC](https://community.cartalk.com/t/diagnosis-puzzler/192756/5 "2023-09-09T02:15:00Z")
Nut behind the wheel?? ---
**Author:** ![bcohen2010](https://avatars.discourse-cdn.com/v4/letter/b/779978/32.png) [@bcohen2010](https://community.cartalk.com/u/bcohen2010)\ **Post date:** [September 9, 2023, 4:03am UTC](https://community.cartalk.com/t/diagnosis-puzzler/192756/6 "2023-09-09T04:03:06Z")
> [@asemaster](#): > > Seriously George, need a bit more info. Would this happen to be a 92 Corolla? Doubtful, because few people would own a scan tool that can work with this type of car. Also, the scan tool would provide limited troubleshooting data, and _not_ include misfire data, fuel trims, etc. ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [September 9, 2023, 8:48pm UTC](https://community.cartalk.com/t/diagnosis-puzzler/192756/7 "2023-09-09T20:48:57Z")
Good guesses from those who ventured , but all incorrect. The EGR valve was stuck open. Citroen Berlingo. ---
**Author:** ![bing](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bing/32/4619_2.png) [@bing](https://community.cartalk.com/u/bing)\ **Post date:** [September 9, 2023, 9:12pm UTC](https://community.cartalk.com/t/diagnosis-puzzler/192756/8 "2023-09-09T21:12:55Z")
Let’s see, last time I opened a hood on a Citroen, . . . In Europe don’t they double grantee them so any problem any time they’ll send a truck for you? ---
**Author:** ![db4690](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/db4690/32/2583_2.png) [@db4690](https://community.cartalk.com/u/db4690)\ **Post date:** [September 10, 2023, 1:32am UTC](https://community.cartalk.com/t/diagnosis-puzzler/192756/9 "2023-09-10T01:32:57Z")
> [@asemaster](#): > > Seriously George, need a bit more info. Would this happen to be a 92 Corolla? George’s 1992 Corolla doesn’t even have a MAF . . . it’s a speed-density system And I think the extent of diagnosis on his car involves retrieving blink codes ---
**Author:** ![asemaster](https://avatars.discourse-cdn.com/v4/letter/a/5f9b8f/32.png) [@asemaster](https://community.cartalk.com/u/asemaster)\ **Post date:** [September 10, 2023, 5:09am UTC](https://community.cartalk.com/t/diagnosis-puzzler/192756/10 "2023-09-10T05:09:24Z")
> [@db4690](#): > > George’s 1992 Corolla doesn’t even have a MAF . . . it’s a speed-density system Yeah, well, I’m getting a few gray hairs, my memory is a little hazy on which Toyotas used a VAF, MAF, or speed density system. 😀 But I do have another question for @George_San_Jose1 , when and how did he have the pleasure of working on a fine Citroen?