DISEASE CHARACTERISTICS: Histologically or cytologically confirmed solid tumor for which no curative or effective therapy is available No symptomatic or uncontrolled brain or leptomeningeal metastasis Irradiated brain metastasis allowed if neurological status is stable 4 weeks after radiotherapy

PATIENT CHARACTERISTICS: Age: Over 18 Performance status: ECOG 0-2 Life expectancy: Not specified Hematopoietic: Platelet count at least 100,000/mm3 Absolute neutrophil count at least 1,500/mm3 Hepatic: SGOT no greater than 1.5 times upper limit of normal (ULN) Bilirubin no greater than ULN No acute hepatitis Renal: Not specified Cardiovascular: No unstable cardiac disease requiring treatment No cardiac arrhythmia No new onset crescendo or rest angina Stable exertional angina allowed Neurological: No symptomatic peripheral neuropathy greater than grade 1 No significant neurological or psychiatric disorders including psychotic disorders, dementia, or seizures Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception during and for 2 weeks following study No other serious illness or medical condition No active infection, including septicemia No severe gastrointestinal bleeding No hypersensitivity to leucovorin calcium or fluorouracil-uracil No psychological, familial, sociological, or geographical condition that would preclude study

PRIOR CONCURRENT THERAPY: Biologic therapy: No concurrent immunotherapy No concurrent colony-stimulating growth factors within 24 hours of fluorouracil-uracil Chemotherapy: No more than 1 prior regimen of chemotherapy Prior taxanes and fluorouracil allowed At least 3 weeks since prior chemotherapy (6 weeks for mitomycin or nitrosoureas) and recovered No other concurrent chemotherapy Endocrine therapy: At least 3 weeks since prior hormonal therapy and recovered No concurrent anti-cancer hormonal agents Radiotherapy: At least 3 weeks since prior radiotherapy and recovered Concurrent radiotherapy allowed for palliation of painful bone metastases, pathologic fractures of known lytic disease, or brain lesions Surgery: Not specified Other: At least 3 weeks since prior investigational drugs No concurrent antiarrhythmic medication No other concurrent investigational therapy No concurrent halogenated anti-viral agent (e.g., lodenosine, fialuridine, clevudine, emtricitabine, or sorivudine)