92E-36 runs awful after filling up and carwash
 

I know...BEFORE YOU YELL AT ME..... I was in a hurry and had to get the wash! i have taken the computer out and it is bone dry with no corrosion...wheeew!
I have been getting killed by the economy so I didn't always use premium gas... for a few months the car ran great... a little hesitation when shifting and the red check engine light would come on... but strangely after the light came on it ran perfect for a few days at any speed...happened like this for months... now the light quit coming on and the hesitation would not go away... went on a 2 hr trip so I filled up with 93 octane and ran through a good car wash...I KNOW!!! ran terrible as soon as I left the filling station... drove it for 2 hrs watched a ballgame and drove 4 hrs runs 85 easy and doesn't sound bad... normal rpm but my gas needle fluctuates noticeably even on straight ways with cruise on...
new parts in past month: new tires & alignment, ac hose, fan clutch, fan blade, auxiliary fan, pcv valve... fuel filter is about 10 months old, but i bought a new one anyway, (haven't put it on yet) I'm thinking vaccum line, o2 sensor, catalytic converter... any ideas?

hmmmm.... nothing?

If the computer is dry and clean, the next suspect is the fuel. Water in gasoline is common. Here in California, a gasoline distributor got busted a few years ago for blending waste industrial solvents in with the fuel. That was quite a scam. They were getting paid to dispose of the hazardous waste, they were getting paid for the waste at fuel prices, and they did not have to pay taxes on the gallons that were waste because those gallons never officially existed in the fuel supply. Chlorinated solvents do not burn well and corrode fuel and exhaust system components.

You can try a bottle of HEET to put any water that may be in the fuel into emulsion so it does not come through in slugs.

Thank you very much:-) my next step is the fuel filter, I will try that this afternoon and I will try and find this "heat"... I have ordered new injectors and a fuel rail with regulator already and just waiting for them... thanks again for your insi:rofl2ght....

just got worse... replaced the fuel filter today, but cant drive it because I found a small fuel leak( bad fuel hose)

Have you examined all the tubing from the mass airflow sensor up to the throttle body? Don't forget the hoses to the idle air control valve under the manifold.

Any of those plastic or rubber parts that have not been replaced in 8+ years could be brittle and cracking, letting in un-metered air. I have replaced a lot of plastic and rubber on my two '97s, and I am starting to replace it on my two '04s.